version bump

fix logger demo
converted the Demo app's observer demo to use CoreStoreObject instead of NSManagedObject
2026-01-12 14:50:29 +01:00 · 2017-06-14 21:50:58 +09:00 · 2017-06-14 17:43:34 +09:00 · 2017-06-14 17:39:57 +09:00 · 2017-06-14 17:37:46 +09:00 · 2017-06-10 23:19:02 +09:00
33 changed files with 1800 additions and 588 deletions
--- a/CoreStore.podspec
+++ b/CoreStore.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
    s.name = "CoreStore"
-    s.version = "4.0.1"
+    s.version = "4.0.5"
    s.license = "MIT"
    s.summary = "Unleashing the real power of Core Data with the elegance and safety of Swift"
    s.homepage = "https://github.com/JohnEstropia/CoreStore"
--- a/CoreStore.xcodeproj/project.pbxproj
+++ b/CoreStore.xcodeproj/project.pbxproj
@@ -238,6 +238,10 @@
 		B538BA781D15B3E30003A766 /* CoreStoreBridge.m in Sources */ = {isa = PBXBuildFile; fileRef = B538BA701D15B3E30003A766 /* CoreStoreBridge.m */; };
 		B538BA791D15B3E30003A766 /* CoreStoreBridge.m in Sources */ = {isa = PBXBuildFile; fileRef = B538BA701D15B3E30003A766 /* CoreStoreBridge.m */; };
 		B538BA7A1D15B3E30003A766 /* CoreStoreBridge.m in Sources */ = {isa = PBXBuildFile; fileRef = B538BA701D15B3E30003A766 /* CoreStoreBridge.m */; };
+		B53B275F1EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = B53B275E1EE3B92E00E9B352 /* CoreStoreManagedObject.swift */; };
+		B53B27601EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = B53B275E1EE3B92E00E9B352 /* CoreStoreManagedObject.swift */; };
+		B53B27611EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = B53B275E1EE3B92E00E9B352 /* CoreStoreManagedObject.swift */; };
+		B53B27621EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = B53B275E1EE3B92E00E9B352 /* CoreStoreManagedObject.swift */; };
 		B53FB9FE1CAB2D2F00F0D40A /* CSMigrationResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = B53FB9FD1CAB2D2F00F0D40A /* CSMigrationResult.swift */; };
 		B53FBA001CAB2D2F00F0D40A /* CSMigrationResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = B53FB9FD1CAB2D2F00F0D40A /* CSMigrationResult.swift */; };
 		B53FBA011CAB2D2F00F0D40A /* CSMigrationResult.swift in Sources */ = {isa = PBXBuildFile; fileRef = B53FB9FD1CAB2D2F00F0D40A /* CSMigrationResult.swift */; };
@@ -752,6 +756,7 @@
 		B52FD3A91E3B3EF10001D919 /* NSManagedObject+Logging.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSManagedObject+Logging.swift"; sourceTree = "<group>"; };
 		B533C4DA1D7D4BFA001383CB /* DispatchQueue+CoreStore.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "DispatchQueue+CoreStore.swift"; sourceTree = "<group>"; };
 		B538BA701D15B3E30003A766 /* CoreStoreBridge.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = CoreStoreBridge.m; sourceTree = "<group>"; };
+		B53B275E1EE3B92E00E9B352 /* CoreStoreManagedObject.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CoreStoreManagedObject.swift; sourceTree = "<group>"; };
 		B53FB9FD1CAB2D2F00F0D40A /* CSMigrationResult.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CSMigrationResult.swift; sourceTree = "<group>"; };
 		B53FBA031CAB300C00F0D40A /* CSMigrationType.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CSMigrationType.swift; sourceTree = "<group>"; };
 		B53FBA0A1CAB5E6500F0D40A /* CSCoreStore+Migrating.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "CSCoreStore+Migrating.swift"; sourceTree = "<group>"; };
@@ -1425,16 +1430,17 @@
 			children = (
 				B5C976E61C6E3A5900B1AF90 /* CoreStoreFetchedResultsController.swift */,
 				B526613F1CADD585007B85D9 /* CoreStoreFetchRequest+CoreStore.swift */,
-				B51260881E9B252B00402229 /* NSEntityDescription+DynamicModel.swift */,
-				B56923C31EB823B4007C4DC9 /* NSEntityDescription+Migration.swift */,
+				B53B275E1EE3B92E00E9B352 /* CoreStoreManagedObject.swift */,
+				B533C4DA1D7D4BFA001383CB /* DispatchQueue+CoreStore.swift */,
 				B51260921E9B28F100402229 /* EntityIdentifier.swift */,
 				B54A6A541BA15F2A007870FD /* FetchedResultsControllerDelegate.swift */,
 				B5E834BA1B7691F3001D3D50 /* Functions.swift */,
 				B5FAD6AB1B51285300714891 /* MigrationManager.swift */,
 				B5E84F2B1AFF849C0064E85B /* NotificationObserver.swift */,
-				B533C4DA1D7D4BFA001383CB /* DispatchQueue+CoreStore.swift */,
-				B52FD3A91E3B3EF10001D919 /* NSManagedObject+Logging.swift */,
+				B51260881E9B252B00402229 /* NSEntityDescription+DynamicModel.swift */,
+				B56923C31EB823B4007C4DC9 /* NSEntityDescription+Migration.swift */,
 				B58D0C621EAA0C7E003EDD87 /* NSManagedObject+DynamicModel.swift */,
+				B52FD3A91E3B3EF10001D919 /* NSManagedObject+Logging.swift */,
 				B5E84F2C1AFF849C0064E85B /* NSManagedObjectContext+CoreStore.swift */,
 				B5E84F351AFF85470064E85B /* NSManagedObjectContext+Querying.swift */,
 				B5E84F321AFF85470064E85B /* NSManagedObjectContext+Setup.swift */,
@@ -1875,6 +1881,7 @@
 				B5E2222A1CA51B6E00BA2E95 /* CSUnsafeDataTransaction.swift in Sources */,
 				B5E84F391AFF85470064E85B /* NSManagedObjectContext+Querying.swift in Sources */,
 				B56923E81EB827F5007C4DC9 /* InferredSchemaMappingProvider.swift in Sources */,
+				B53B275F1EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */,
 				B5D33A011E96012400C880DE /* Relationship.swift in Sources */,
 				B5E84EE81AFF84610064E85B /* CoreStoreLogger.swift in Sources */,
 				B56923C91EB82410007C4DC9 /* NSManagedObjectModel+Migration.swift in Sources */,
@@ -2059,6 +2066,7 @@
 				82BA18A71C4BBD2900A0916E /* CoreStore+Logging.swift in Sources */,
 				82BA18D81C4BBD7100A0916E /* WeakObject.swift in Sources */,
 				B56923E91EB827F5007C4DC9 /* InferredSchemaMappingProvider.swift in Sources */,
+				B53B27601EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */,
 				B5D33A021E96012400C880DE /* Relationship.swift in Sources */,
 				B559CD4B1CAA8C6D00E4D58B /* CSStorageInterface.swift in Sources */,
 				B56923CA1EB82410007C4DC9 /* NSManagedObjectModel+Migration.swift in Sources */,
@@ -2243,6 +2251,7 @@
 				B52DD1A71BE1F93200949AFE /* BaseDataTransaction+Querying.swift in Sources */,
 				B546F96C1C9AF26D00D5AC55 /* CSInMemoryStore.swift in Sources */,
 				B56923EB1EB827F5007C4DC9 /* InferredSchemaMappingProvider.swift in Sources */,
+				B53B27621EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */,
 				B5D33A041E96012400C880DE /* Relationship.swift in Sources */,
 				B52DD1C61BE1F94600949AFE /* NSManagedObjectContext+CoreStore.swift in Sources */,
 				B56923CC1EB82410007C4DC9 /* NSManagedObjectModel+Migration.swift in Sources */,
@@ -2427,6 +2436,7 @@
 				B563219F1BD65216006C9394 /* ObjectMonitor.swift in Sources */,
 				B56321B61BD6521C006C9394 /* WeakObject.swift in Sources */,
 				B56923EA1EB827F5007C4DC9 /* InferredSchemaMappingProvider.swift in Sources */,
+				B53B27611EE3B92E00E9B352 /* CoreStoreManagedObject.swift in Sources */,
 				B5D33A031E96012400C880DE /* Relationship.swift in Sources */,
 				B559CD4C1CAA8C6D00E4D58B /* CSStorageInterface.swift in Sources */,
 				B56923CB1EB82410007C4DC9 /* NSManagedObjectModel+Migration.swift in Sources */,
--- a/CoreStoreDemo/CoreStoreDemo/CoreStoreDemo.xcdatamodeld/CoreStoreDemo.xcdatamodel/contents
+++ b/CoreStoreDemo/CoreStoreDemo/CoreStoreDemo.xcdatamodeld/CoreStoreDemo.xcdatamodel/contents
@@ -1,36 +1,25 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model userDefinedModelVersionIdentifier="" type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="10169.1" systemVersion="15D21" minimumToolsVersion="Automatic">
-    <entity name="Palette" representedClassName="CoreStoreDemo.Palette">
-        <attribute name="brightness" optional="YES" attributeType="Float" defaultValueString="0.0" syncable="YES"/>
-        <attribute name="colorName" optional="YES" transient="YES" attributeType="String" syncable="YES"/>
-        <attribute name="hue" optional="YES" attributeType="Integer 32" defaultValueString="0.0" syncable="YES"/>
-        <attribute name="saturation" optional="YES" attributeType="Float" defaultValueString="0.0" syncable="YES"/>
-        <userInfo/>
-    </entity>
+<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="12141" systemVersion="16F73" minimumToolsVersion="Xcode 7.3" sourceLanguage="Objective-C" userDefinedModelVersionIdentifier="">
    <entity name="Place" representedClassName="CoreStoreDemo.Place" syncable="YES">
-        <attribute name="latitude" optional="YES" attributeType="Double" defaultValueString="0.0" syncable="YES"/>
-        <attribute name="longitude" optional="YES" attributeType="Double" defaultValueString="0.0" syncable="YES"/>
+        <attribute name="latitude" optional="YES" attributeType="Double" defaultValueString="0.0" usesScalarValueType="NO" syncable="YES"/>
+        <attribute name="longitude" optional="YES" attributeType="Double" defaultValueString="0.0" usesScalarValueType="NO" syncable="YES"/>
        <attribute name="subtitle" optional="YES" attributeType="String" syncable="YES"/>
        <attribute name="title" optional="YES" attributeType="String" syncable="YES"/>
    </entity>
    <entity name="TimeZone" representedClassName="CoreStoreDemo.TimeZone" syncable="YES">
        <attribute name="abbreviation" optional="YES" attributeType="String" syncable="YES"/>
-        <attribute name="daylightSavingTimeOffset" optional="YES" attributeType="Double" defaultValueString="0.0" syncable="YES"/>
-        <attribute name="hasDaylightSavingTime" optional="YES" attributeType="Boolean" syncable="YES"/>
+        <attribute name="daylightSavingTimeOffset" optional="YES" attributeType="Double" defaultValueString="0.0" usesScalarValueType="NO" syncable="YES"/>
+        <attribute name="hasDaylightSavingTime" optional="YES" attributeType="Boolean" usesScalarValueType="NO" syncable="YES"/>
        <attribute name="name" optional="YES" attributeType="String" syncable="YES"/>
-        <attribute name="secondsFromGMT" optional="YES" attributeType="Integer 32" defaultValueString="0.0" syncable="YES"/>
+        <attribute name="secondsFromGMT" optional="YES" attributeType="Integer 32" defaultValueString="0.0" usesScalarValueType="NO" syncable="YES"/>
    </entity>
    <configuration name="FetchingAndQueryingDemo">
        <memberEntity name="TimeZone"/>
    </configuration>
-    <configuration name="ObservingDemo">
-        <memberEntity name="Palette"/>
-    </configuration>
    <configuration name="TransactionsDemo">
        <memberEntity name="Place"/>
    </configuration>
    <elements>
-        <element name="Palette" positionX="261" positionY="189" width="128" height="105"/>
        <element name="Place" positionX="261" positionY="225" width="128" height="105"/>
        <element name="TimeZone" positionX="297" positionY="270" width="128" height="120"/>
    </elements>
--- a/CoreStoreDemo/CoreStoreDemo/Info.plist
+++ b/CoreStoreDemo/CoreStoreDemo/Info.plist
@@ -17,7 +17,7 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>4.0.1</string>
+	<string>4.0.3</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
--- a/Demo/ListObserverDemoViewController.swift
+++ b/Demo/ListObserverDemoViewController.swift
@@ -10,7 +10,7 @@ import UIKit
 import CoreStore


-private struct Static {
+struct ColorsDemo {
    
    enum Filter: String {
        
@@ -33,8 +33,8 @@ private struct Static {
            switch self {
                
            case .all: return Where(true)
-            case .light: return Where("%K >= %@", #keyPath(Palette.brightness), 0.9)
-            case .dark: return Where("%K <= %@", #keyPath(Palette.brightness), 0.4)
+            case .light: return Palette.where({ $0.brightness >= 0.9 })
+            case .dark: return Palette.where({ $0.brightness <= 0.4 })
            }
        }
    }
@@ -45,25 +45,38 @@ private struct Static {
            
            self.palettes.refetch(
                self.filter.whereClause(),
-                OrderBy(.ascending(#keyPath(Palette.hue)))
+                Palette.orderBy(ascending: { $0.hue })
            )
        }
    }
    
+    static let stack: DataStack = {
+     
+        return DataStack(
+            CoreStoreSchema(
+                modelVersion: "ColorsDemo",
+                entities: [
+                    Entity<Palette>("Palette"),
+                ],
+                versionLock: [
+                    "Palette": [0x8c25aa53c7c90a28, 0xa243a34d25f1a3a7, 0x56565b6935b6055a, 0x4f988bb257bf274f]
+                ]
+            )
+        )
+    }()
+    
    static let palettes: ListMonitor<Palette> = {
        
-        try! CoreStore.addStorageAndWait(
+        try! ColorsDemo.stack.addStorageAndWait(
            SQLiteStore(
                fileName: "ColorsDemo.sqlite",
-                configuration: "ObservingDemo",
                localStorageOptions: .recreateStoreOnModelMismatch
            )
        )
-        
-        return CoreStore.monitorSectionedList(
+        return ColorsDemo.stack.monitorSectionedList(
            From<Palette>(),
-            SectionBy(#keyPath(Palette.colorName)),
-            OrderBy(.ascending(#keyPath(Palette.hue)))
+            SectionBy(Palette.keyPath({ $0.colorName })),
+            Palette.orderBy(ascending: { $0.hue })
        )
    }()
 }
@@ -77,7 +90,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
    
    deinit {
        
-        Static.palettes.removeObserver(self)
+        ColorsDemo.palettes.removeObserver(self)
    }
    
    
@@ -98,7 +111,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
        ]
        
        let filterBarButton = UIBarButtonItem(
-            title: Static.filter.rawValue,
+            title: ColorsDemo.filter.rawValue,
            style: .plain,
            target: self,
            action: #selector(self.filterBarButtonItemTouched(_:))
@@ -113,9 +126,9 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
        ]
        self.filterBarButton = filterBarButton
        
-        Static.palettes.addObserver(self)
+        ColorsDemo.palettes.addObserver(self)
        
-        self.setTable(enabled: !Static.palettes.isPendingRefetch)
+        self.setTable(enabled: !ColorsDemo.palettes.isPendingRefetch)
    }
    
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
@@ -137,19 +150,19 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
    
    override func numberOfSections(in tableView: UITableView) -> Int {
        
-        return Static.palettes.numberOfSections()
+        return ColorsDemo.palettes.numberOfSections()
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        
-        return Static.palettes.numberOfObjectsInSection(section)
+        return ColorsDemo.palettes.numberOfObjectsInSection(section)
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "PaletteTableViewCell") as! PaletteTableViewCell
        
-        let palette = Static.palettes[indexPath]
+        let palette = ColorsDemo.palettes[indexPath]
        cell.colorView?.backgroundColor = palette.color
        cell.label?.text = palette.colorText
        
@@ -165,7 +178,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
        
        self.performSegue(
            withIdentifier: "ObjectObserverDemoViewController",
-            sender: Static.palettes[indexPath]
+            sender: ColorsDemo.palettes[indexPath]
        )
    }
    
@@ -174,8 +187,8 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
        switch editingStyle {
            
        case .delete:
-            let palette = Static.palettes[indexPath]
-            CoreStore.perform(
+            let palette = ColorsDemo.palettes[indexPath]
+            ColorsDemo.stack.perform(
                asynchronous: { (transaction) in
                    
                    transaction.delete(palette)
@@ -190,7 +203,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
    
    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        
-        return Static.palettes.sectionInfoAtIndex(section).name
+        return ColorsDemo.palettes.sectionInfoAtIndex(section).name
    }
    
    
@@ -213,7 +226,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
    
    func listMonitorDidRefetch(_ monitor: ListMonitor<Palette>) {
        
-        self.filterBarButton?.title = Static.filter.rawValue
+        self.filterBarButton?.title = ColorsDemo.filter.rawValue
        self.tableView.reloadData()
        self.setTable(enabled: true)
    }
@@ -235,7 +248,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
        
        if let cell = self.tableView.cellForRow(at: indexPath) as? PaletteTableViewCell {
            
-            let palette = Static.palettes[indexPath]
+            let palette = ColorsDemo.palettes[indexPath]
            cell.colorView?.backgroundColor = palette.color
            cell.label?.text = palette.colorText
        }
@@ -268,7 +281,7 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
    
    @IBAction private dynamic func resetBarButtonItemTouched(_ sender: AnyObject?) {
        
-        CoreStore.perform(
+        ColorsDemo.stack.perform(
            asynchronous: { (transaction) in
                
                transaction.deleteAll(From<Palette>())
@@ -279,16 +292,16 @@ class ListObserverDemoViewController: UITableViewController, ListSectionObserver
    
    @IBAction private dynamic func filterBarButtonItemTouched(_ sender: AnyObject?) {
        
-        Static.filter = Static.filter.next()
+        ColorsDemo.filter = ColorsDemo.filter.next()
    }
    
    @IBAction private dynamic func addBarButtonItemTouched(_ sender: AnyObject?) {
        
-        CoreStore.perform(
+        ColorsDemo.stack.perform(
            asynchronous: { (transaction) in
                
                let palette = transaction.create(Into<Palette>())
-                palette.setInitialValues()
+                palette.setInitialValues(in: transaction)
            },
            completion: { _ in }
        )
--- a/Demo/ObjectObserverDemoViewController.swift
+++ b/Demo/ObjectObserverDemoViewController.swift
@@ -29,7 +29,7 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
            
            if let palette = newValue {
                
-                self.monitor = CoreStore.monitorObject(palette)
+                self.monitor = ColorsDemo.stack.monitorObject(palette)
            }
            else {
                
@@ -50,22 +50,22 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
    
    required init?(coder aDecoder: NSCoder) {
        
-        if let palette = CoreStore.fetchOne(From<Palette>(), OrderBy(.ascending(#keyPath(Palette.hue)))) {
+        if let palette = ColorsDemo.stack.fetchOne(From<Palette>(), Palette.orderBy(ascending: { $0.hue })) {
            
-            self.monitor = CoreStore.monitorObject(palette)
+            self.monitor = ColorsDemo.stack.monitorObject(palette)
        }
        else {
            
-            _ = try? CoreStore.perform(
+            _ = try? ColorsDemo.stack.perform(
                synchronous: { (transaction) in
                    
-                    let palette = transaction.create(Into(Palette.self))
-                    palette.setInitialValues()
+                    let palette = transaction.create(Into<Palette>())
+                    palette.setInitialValues(in: transaction)
                }
            )
            
-            let palette = CoreStore.fetchOne(From<Palette>(), OrderBy(.ascending(#keyPath(Palette.hue))))!
-            self.monitor = CoreStore.monitorObject(palette)
+            let palette = ColorsDemo.stack.fetchOne(From<Palette>(), Palette.orderBy(ascending: { $0.hue }))!
+            self.monitor = ColorsDemo.stack.monitorObject(palette)
        }
        
        super.init(coder: aDecoder)
@@ -121,12 +121,12 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
    @IBAction dynamic func hueSliderValueDidChange(_ sender: AnyObject?) {
        
        let hue = self.hueSlider?.value ?? 0
-        CoreStore.perform(
+        ColorsDemo.stack.perform(
            asynchronous: { [weak self] (transaction) in
                
                if let palette = transaction.edit(self?.monitor?.object) {
                    
-                    palette.hue = Int32(hue)
+                    palette.hue .= Int(hue)
                }
            },
            completion: { _ in }
@@ -136,12 +136,12 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
    @IBAction dynamic func saturationSliderValueDidChange(_ sender: AnyObject?) {
        
        let saturation = self.saturationSlider?.value ?? 0
-        CoreStore.perform(
+        ColorsDemo.stack.perform(
            asynchronous: { [weak self] (transaction) in
                
                if let palette = transaction.edit(self?.monitor?.object) {
                    
-                    palette.saturation = saturation
+                    palette.saturation .= saturation
                }
            },
            completion: { _ in }
@@ -151,12 +151,12 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
    @IBAction dynamic func brightnessSliderValueDidChange(_ sender: AnyObject?) {
        
        let brightness = self.brightnessSlider?.value ?? 0
-        CoreStore.perform(
+        ColorsDemo.stack.perform(
            asynchronous: { [weak self] (transaction) in
                
                if let palette = transaction.edit(self?.monitor?.object) {
                    
-                    palette.brightness = brightness
+                    palette.brightness .= brightness
                }
            },
            completion: { _ in }
@@ -165,7 +165,7 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
    
    @IBAction dynamic func deleteBarButtonTapped(_ sender: AnyObject?) {
        
-        CoreStore.perform(
+        ColorsDemo.stack.perform(
            asynchronous: { [weak self] (transaction) in
                
                transaction.delete(self?.monitor?.object)
@@ -176,7 +176,7 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
    
    func reloadPaletteInfo(_ palette: Palette, changedKeys: Set<String>?) {
        
-        self.colorNameLabel?.text = palette.colorName
+        self.colorNameLabel?.text = palette.colorName.value
        
        let color = palette.color
        self.colorNameLabel?.textColor = color
@@ -184,17 +184,17 @@ class ObjectObserverDemoViewController: UIViewController, ObjectObserver {
        
        self.hsbLabel?.text = palette.colorText
        
-        if changedKeys == nil || changedKeys?.contains(#keyPath(Palette.hue)) == true {
+        if changedKeys == nil || changedKeys?.contains(Palette.keyPath{ $0.hue }) == true {
            
-            self.hueSlider?.value = Float(palette.hue)
+            self.hueSlider?.value = Float(palette.hue.value)
        }
-        if changedKeys == nil || changedKeys?.contains(#keyPath(Palette.saturation)) == true {
+        if changedKeys == nil || changedKeys?.contains(Palette.keyPath{ $0.saturation }) == true {
            
-            self.saturationSlider?.value = palette.saturation
+            self.saturationSlider?.value = palette.saturation.value
        }
-        if changedKeys == nil || changedKeys?.contains(#keyPath(Palette.brightness)) == true {
+        if changedKeys == nil || changedKeys?.contains(Palette.keyPath{ $0.brightness }) == true {
            
-            self.brightnessSlider?.value = palette.brightness
+            self.brightnessSlider?.value = palette.brightness.value
        }
    }
 }
--- a/CoreStoreDemo/CoreStoreDemo/List
+++ b/CoreStoreDemo/CoreStoreDemo/List
@@ -14,64 +14,65 @@ import CoreStore

 // MARK: - Palette

-class Palette: NSManagedObject {
-
-    @NSManaged var hue: Int32
-    @NSManaged var saturation: Float
-    @NSManaged var brightness: Float
+final class Palette: CoreStoreObject {
    
-    @objc dynamic var colorName: String {
+    let hue = Value.Required<Int>("hue")
+    let saturation = Value.Required<Float>("saturation")
+    let brightness = Value.Required<Float>("brightness")
+    
+    let colorName = Value.Optional<String>(
+        "colorName",
+        isTransient: true,
+        customGetter: Palette.getCachedColorName
+    )
+    
+    private static func getCachedColorName(_ instance: Palette, _ getValue: () -> String?) -> String? {
        
-        get {
+        if let colorName = getValue() {
            
-            let KVCKey = #keyPath(Palette.colorName)
-            if let colorName = self.getValue(forKvcKey: KVCKey) as? String {
-                
-                return colorName
-            }
-            
-            let colorName: String
-            switch self.hue % 360 {
-                
-            case 0 ..< 20: colorName = "Lower Reds"
-            case 20 ..< 57: colorName = "Oranges and Browns"
-            case 57 ..< 90: colorName = "Yellow-Greens"
-            case 90 ..< 159: colorName = "Greens"
-            case 159 ..< 197: colorName = "Blue-Greens"
-            case 197 ..< 241: colorName = "Blues"
-            case 241 ..< 297: colorName = "Violets"
-            case 297 ..< 331: colorName = "Magentas"
-            default: colorName = "Upper Reds"
-            }
-            
-            self.setPrimitiveValue(colorName, forKey: KVCKey)
            return colorName
        }
-        set {
+        
+        let colorName: String
+        switch instance.hue.value % 360 {
            
-            self.setValue(newValue.cs_toImportableNativeType(), forKvcKey: #keyPath(Palette.colorName))
+        case 0 ..< 20: colorName = "Lower Reds"
+        case 20 ..< 57: colorName = "Oranges and Browns"
+        case 57 ..< 90: colorName = "Yellow-Greens"
+        case 90 ..< 159: colorName = "Greens"
+        case 159 ..< 197: colorName = "Blue-Greens"
+        case 197 ..< 241: colorName = "Blues"
+        case 241 ..< 297: colorName = "Violets"
+        case 297 ..< 331: colorName = "Magentas"
+        default: colorName = "Upper Reds"
        }
+        
+        instance.colorName.primitiveValue = colorName
+        return colorName
    }
+}
+
+extension Palette {
    
    var color: UIColor {
        
        return UIColor(
-            hue: CGFloat(self.hue) / 360.0,
-            saturation: CGFloat(self.saturation),
-            brightness: CGFloat(self.brightness),
+            hue: CGFloat(self.hue.value) / 360.0,
+            saturation: CGFloat(self.saturation.value),
+            brightness: CGFloat(self.brightness.value),
            alpha: 1.0
        )
    }
    
    var colorText: String {
        
-        return "H: \(self.hue)˚, S: \(round(self.saturation * 100.0))%, B: \(round(self.brightness * 100.0))%"
+        return "H: \(self.hue.value)˚, S: \(round(self.saturation.value * 100.0))%, B: \(round(self.brightness.value * 100.0))%"
    }
    
-    func setInitialValues() {
+    func setInitialValues(in transaction: BaseDataTransaction) {
        
-        self.hue = Int32(arc4random_uniform(360))
-        self.saturation = 1.0
-        self.brightness = Float(arc4random_uniform(70) + 30) / 100.0
+        self.hue .= Int(arc4random_uniform(360))
+        self.saturation .= Float(1.0)
+        self.brightness .= Float(arc4random_uniform(70) + 30) / 100.0
    }
 }
--- a/Demo/CustomLoggerViewController.swift
+++ b/Demo/CustomLoggerViewController.swift
@@ -113,7 +113,7 @@ class CustomLoggerViewController: UIViewController, CoreStoreLogger {
        case 2?:
            DispatchQueue.global(qos: .background).async {
                
-                _ = self.dataStack.fetchOne(From<Palette>())
+                _ = self.dataStack.fetchOne(From<Place>())
            }
            
        default:
--- a/Demo/MigrationsDemoViewController.swift
+++ b/Demo/MigrationsDemoViewController.swift
@@ -46,7 +46,7 @@ class MigrationsDemoViewController: UIViewController, ListObserver, UITableViewD
        self.present(alert, animated: true, completion: nil)
        
        
-        let modelMetadata = withExtendedLifetime(DataStack(modelName: "MigrationDemo")) {
+        let modelMetadata = withExtendedLifetime(DataStack(xcodeModelName: "MigrationDemo")) {
            (dataStack: DataStack) -> ModelMetadata in
            
            let models = self.models
--- a/Demo/StackSetupDemoViewController.swift
+++ b/Demo/StackSetupDemoViewController.swift
@@ -17,7 +17,7 @@ private struct Static {
    
    static let facebookStack: DataStack = {
        
-        let dataStack = DataStack(modelName: "StackSetupDemo")
+        let dataStack = DataStack(xcodeModelName: "StackSetupDemo")
        try! dataStack.addStorageAndWait(
            SQLiteStore(
                fileName: "AccountsDemo_FB_Male.sqlite",
@@ -55,7 +55,7 @@ private struct Static {
    
    static let twitterStack: DataStack = {
        
-        let dataStack = DataStack(modelName: "StackSetupDemo")
+        let dataStack = DataStack(xcodeModelName: "StackSetupDemo")
        try! dataStack.addStorageAndWait(
            SQLiteStore(
                fileName: "AccountsDemo_TW_Male.sqlite",
--- a/CoreStoreTests/DynamicModelTests.swift
+++ b/CoreStoreTests/DynamicModelTests.swift
@@ -51,15 +51,49 @@ class Dog: Animal {
 }

 class Person: CoreStoreObject {
-    let title = Value.Required<String>("title", default: "Mr.")
-    let name = Value.Required<String>(
-        "name",
-        customGetter: { (`self`, getValue) in
+    let title = Value.Required<String>(
+        "title",
+        default: "Mr.",
+        customSetter: { (`self`, setValue, originalNewValue) in
            
-            return "\(self.title.value) \(getValue())"
+            setValue(originalNewValue)
+            self.displayName .= nil
        }
    )
+    let name = Value.Required<String>(
+        "name",
+        customSetter: { (`self`, setValue, originalNewValue) in
+            
+            setValue(originalNewValue)
+            self.displayName .= nil
+        }
+    )
+    let displayName = Value.Optional<String>(
+        "displayName",
+        isTransient: true,
+        customGetter: Person.cachedDisplayName(_:_:),
+        affectedByKeyPaths: Person.keyPathsAffectingDisplayName()
+    )
    let pets = Relationship.ToManyUnordered<Animal>("pets", inverse: { $0.master })
+    
+    static func cachedDisplayName(_ instance: Person, _ getValue: () -> String?) -> String? {
+        
+        if let cached = getValue() {
+            
+            return cached
+        }
+        let primitiveValue = "\(instance.title.value) \(instance.name.value)"
+        instance.displayName .= primitiveValue
+        return primitiveValue
+    }
+    
+    static func keyPathsAffectingDisplayName() -> Set<String> {
+        
+        return [
+            self.keyPath({ $0.title }),
+            self.keyPath({ $0.name })
+        ]
+    }
 }


@@ -124,11 +158,25 @@ class DynamicModelTests: BaseTestDataTestCase {
                    let person = transaction.create(Into<Person>())
                    XCTAssertTrue(person.pets.value.isEmpty)
                    
+                    XCTAssertEqual(
+                        object_getClass(person.rawObject!).keyPathsForValuesAffectingValue(forKey: "displayName"),
+                        ["title", "name"]
+                    )
+                    
+                    person.name .= "Joe"
+                    
+                    XCTAssertEqual(person.rawObject!.value(forKey: "name") as! String?, "Joe")
+                    XCTAssertEqual(person.rawObject!.value(forKey: "displayName") as! String?, "Mr. Joe")
+                    
+                    person.rawObject!.setValue("AAAA", forKey: "displayName")
+                    XCTAssertEqual(person.rawObject!.value(forKey: "displayName") as! String?, "AAAA")
+                    
                    person.name .= "John"
-                    XCTAssertEqual(person.name.value, "Mr. John") // Custom getter
+                    XCTAssertEqual(person.name.value, "John")
+                    XCTAssertEqual(person.displayName.value, "Mr. John") // Custom getter
                    
                    person.title .= "Sir"
-                    XCTAssertEqual(person.name.value, "Sir John")
+                    XCTAssertEqual(person.displayName.value, "Sir John")
                    
                    person.pets.value.insert(dog)
                    XCTAssertEqual(person.pets.count, 1)
--- a/README.md
+++ b/README.md
@@ -19,6 +19,7 @@ Unleashing the real power of Core Data with the elegance and safety of Swift
 </p>

 * **Swift 3.1:** iOS 8+ / macOS 10.10+ / watchOS 2.0+ / tvOS 9.0+
+* Beta support: [Swift 3.2](https://github.com/JohnEstropia/CoreStore/tree/prototype/Swift_3_2), [Swift 4.0](https://github.com/JohnEstropia/CoreStore/tree/prototype/Swift_4_0)

 Upgrading from CoreStore 3.x to 4.x? Check out the [new features](#features) and make sure to read the [Migration guide](#upgrading-from-3xx-to-4xx).

@@ -460,6 +461,55 @@ CoreStore.defaultStack = DataStack(
 )   
 ```

+**`CoreStoreSchema`-based model versions with progressive migration**
+```swift
+typealias Animal = V2.Animal
+typealias Dog = V2.Dog
+typealias Person = V2.Person
+enum V2 {
+    class Animal: CoreStoreObject {
+        // ...
+    }
+    class Dog: Animal {
+        // ...
+    }
+    class Person: CoreStoreObject {
+        // ...
+    }
+}
+enum V1 {
+    class Animal: CoreStoreObject {
+        // ...
+    }
+    class Dog: Animal {
+        // ...
+    }
+    class Person: CoreStoreObject {
+        // ...
+    }
+}
+
+CoreStore.defaultStack = DataStack(
+    CoreStoreSchema(
+        modelVersion: "V1",
+        entities: [
+            Entity<V1.Animal>("Animal", isAbstract: true),
+            Entity<V1.Dog>("Dog"),
+            Entity<V1.Person>("Person")
+        ]
+    ),
+    CoreStoreSchema(
+        modelVersion: "V2",
+        entities: [
+            Entity<V2.Animal>("Animal", isAbstract: true),
+            Entity<V2.Dog>("Dog"),
+            Entity<V2.Person>("Person")
+        ]
+    ),
+    migrationChain: ["V1", "V2"]
+)
+```
+

 ### Starting migrations
 We have seen `addStorageAndWait(...)` used to initialize our persistent store. As the method name's *~AndWait* suffix suggests though, this method blocks so it should not do long tasks such as store migrations. In fact CoreStore will only attempt a synchronous **lightweight** migration if you explicitly provide the `.allowSynchronousLightweightMigration` option:
--- a/Sources/CSAsynchronousDataTransaction.swift
+++ b/Sources/CSAsynchronousDataTransaction.swift
@@ -35,7 +35,7 @@ import CoreData
 - SeeAlso: `AsynchronousDataTransaction`
 */
@objc
-public final class CSAsynchronousDataTransaction: CSBaseDataTransaction {
+public final class CSAsynchronousDataTransaction: CSBaseDataTransaction, CoreStoreObjectiveCType {
    
    /**
     Saves the transaction changes. This method should not be used after the `-commitWithCompletion:` method was already called once.
@@ -139,9 +139,9 @@ public final class CSAsynchronousDataTransaction: CSBaseDataTransaction {
    
    public typealias SwiftType = AsynchronousDataTransaction
    
-    public override var bridgeToSwift: AsynchronousDataTransaction {
+    public var bridgeToSwift: AsynchronousDataTransaction {
        
-        return super.bridgeToSwift as! AsynchronousDataTransaction
+        return super.swiftTransaction as! AsynchronousDataTransaction
    }
    
    public required init(_ swiftValue: AsynchronousDataTransaction) {
@@ -149,9 +149,9 @@ public final class CSAsynchronousDataTransaction: CSBaseDataTransaction {
        super.init(swiftValue as BaseDataTransaction)
    }
    
-    public required init(_ swiftValue: BaseDataTransaction) {
+    public required override init(_ swiftValue: BaseDataTransaction) {
        
-        super.init(swiftValue as! AsynchronousDataTransaction)
+        super.init(swiftValue)
    }
    
    
--- a/Sources/CSBaseDataTransaction+Querying.swift
+++ b/Sources/CSBaseDataTransaction+Querying.swift
@@ -40,7 +40,7 @@ public extension CSBaseDataTransaction {
    @objc
    public func fetchExistingObject(_ object: NSManagedObject) -> Any? {
        
-        return self.bridgeToSwift.context.fetchExisting(object) as NSManagedObject?
+        return self.swiftTransaction.context.fetchExisting(object) as NSManagedObject?
    }
    
    /**
@@ -52,7 +52,7 @@ public extension CSBaseDataTransaction {
    @objc
    public func fetchExistingObjectWithID(_ objectID: NSManagedObjectID) -> Any? {
        
-        return self.bridgeToSwift.context.fetchExisting(objectID) as NSManagedObject?
+        return self.swiftTransaction.context.fetchExisting(objectID) as NSManagedObject?
    }
    
    /**
@@ -64,7 +64,7 @@ public extension CSBaseDataTransaction {
    @objc
    public func fetchExistingObjects(_ objects: [NSManagedObject]) -> [Any] {
        
-        return self.bridgeToSwift.context.fetchExisting(objects) as [NSManagedObject]
+        return self.swiftTransaction.context.fetchExisting(objects) as [NSManagedObject]
    }
    
    /**
@@ -76,7 +76,7 @@ public extension CSBaseDataTransaction {
    @objc
    public func fetchExistingObjectsWithIDs(_ objectIDs: [NSManagedObjectID]) -> [Any] {
        
-        return self.bridgeToSwift.context.fetchExisting(objectIDs) as [NSManagedObject]
+        return self.swiftTransaction.context.fetchExisting(objectIDs) as [NSManagedObject]
    }
    
    /**
@@ -90,10 +90,10 @@ public extension CSBaseDataTransaction {
    public func fetchOneFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> Any? {
        
        CoreStore.assert(
-            self.bridgeToSwift.isRunningInAllowedQueue(),
+            self.swiftTransaction.isRunningInAllowedQueue(),
            "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
        )
-        return self.bridgeToSwift.context.fetchOne(from, fetchClauses)
+        return self.swiftTransaction.context.fetchOne(from, fetchClauses)
    }
    
    /**
@@ -107,10 +107,10 @@ public extension CSBaseDataTransaction {
    public func fetchAllFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> [Any]? {
        
        CoreStore.assert(
-            self.bridgeToSwift.isRunningInAllowedQueue(),
+            self.swiftTransaction.isRunningInAllowedQueue(),
            "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
        )
-        return self.bridgeToSwift.context.fetchAll(from, fetchClauses)
+        return self.swiftTransaction.context.fetchAll(from, fetchClauses)
    }
    
    /**
@@ -124,10 +124,10 @@ public extension CSBaseDataTransaction {
    public func fetchCountFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> NSNumber? {
        
        CoreStore.assert(
-            self.bridgeToSwift.isRunningInAllowedQueue(),
+            self.swiftTransaction.isRunningInAllowedQueue(),
            "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
        )
-        return self.bridgeToSwift.context
+        return self.swiftTransaction.context
            .fetchCount(from, fetchClauses)
            .flatMap { NSNumber(value: $0) }
    }
@@ -143,10 +143,10 @@ public extension CSBaseDataTransaction {
    public func fetchObjectIDFrom(_ from: CSFrom, fetchClauses: [CSFetchClause]) -> NSManagedObjectID? {
        
        CoreStore.assert(
-            self.bridgeToSwift.isRunningInAllowedQueue(),
+            self.swiftTransaction.isRunningInAllowedQueue(),
            "Attempted to fetch from a \(cs_typeName(self)) outside its designated queue."
        )
-        return self.bridgeToSwift.context.fetchObjectID(from, fetchClauses)
+        return self.swiftTransaction.context.fetchObjectID(from, fetchClauses)
    }
    
    /**
@@ -163,10 +163,10 @@ public extension CSBaseDataTransaction {
    public func queryValueFrom(_ from: CSFrom, selectClause: CSSelect, queryClauses: [CSQueryClause]) -> Any? {
        
        CoreStore.assert(
-            self.bridgeToSwift.isRunningInAllowedQueue(),
+            self.swiftTransaction.isRunningInAllowedQueue(),
            "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
        )
-        return self.bridgeToSwift.context.queryValue(from, selectClause, queryClauses)
+        return self.swiftTransaction.context.queryValue(from, selectClause, queryClauses)
    }
    
    /**
@@ -183,9 +183,9 @@ public extension CSBaseDataTransaction {
    public func queryAttributesFrom(_ from: CSFrom, selectClause: CSSelect, queryClauses: [CSQueryClause]) -> [[String: Any]]? {
        
        CoreStore.assert(
-            self.bridgeToSwift.isRunningInAllowedQueue(),
+            self.swiftTransaction.isRunningInAllowedQueue(),
            "Attempted to query from a \(cs_typeName(self)) outside its designated queue."
        )
-        return self.bridgeToSwift.context.queryAttributes(from, selectClause, queryClauses)
+        return self.swiftTransaction.context.queryAttributes(from, selectClause, queryClauses)
    }
 }
--- a/Sources/CSBaseDataTransaction.swift
+++ b/Sources/CSBaseDataTransaction.swift
@@ -35,7 +35,7 @@ import CoreData
 - SeeAlso: `BaseDataTransaction`
 */
@objc
-public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
+public class CSBaseDataTransaction: NSObject {
    
    // MARK: Object management
    
@@ -45,7 +45,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public var hasChanges: Bool {
        
-        return self.bridgeToSwift.hasChanges
+        return self.swiftTransaction.hasChanges
    }
    
    /**
@@ -57,7 +57,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func createInto(_ into: CSInto) -> Any {
        
-        return self.bridgeToSwift.create(into.bridgeToSwift)
+        return self.swiftTransaction.create(into.bridgeToSwift)
    }
    
    /**
@@ -69,7 +69,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func editObject(_ object: NSManagedObject?) -> Any? {
        
-        return self.bridgeToSwift.edit(object)
+        return self.swiftTransaction.edit(object)
    }
    
    /**
@@ -82,7 +82,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func editInto(_ into: CSInto, objectID: NSManagedObjectID) -> Any? {
        
-        return self.bridgeToSwift.edit(into.bridgeToSwift, objectID)
+        return self.swiftTransaction.edit(into.bridgeToSwift, objectID)
    }

    /**
@@ -93,7 +93,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func deleteObject(_ object: NSManagedObject?) {
        
-        self.bridgeToSwift.delete(object)
+        self.swiftTransaction.delete(object)
    }
    
    /**
@@ -104,7 +104,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func deleteObjects(_ objects: [NSManagedObject]) {
        
-        self.bridgeToSwift.delete(objects)
+        self.swiftTransaction.delete(objects)
    }
    
    /**
@@ -113,7 +113,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func refreshAndMergeAllObjects() {
        
-        self.bridgeToSwift.refreshAndMergeAllObjects()
+        self.swiftTransaction.refreshAndMergeAllObjects()
    }
    
    
@@ -128,7 +128,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func insertedObjectsOfType(_ entity: NSManagedObject.Type) -> Set<NSManagedObject> {
        
-        return self.bridgeToSwift.insertedObjects(entity)
+        return self.swiftTransaction.insertedObjects(entity)
    }
    
    /**
@@ -139,7 +139,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func insertedObjectIDs() -> Set<NSManagedObjectID> {
        
-        return self.bridgeToSwift.insertedObjectIDs()
+        return self.swiftTransaction.insertedObjectIDs()
    }
    
    /**
@@ -151,7 +151,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func insertedObjectIDsOfType(_ entity: NSManagedObject.Type) -> Set<NSManagedObjectID> {
        
-        return self.bridgeToSwift.insertedObjectIDs(entity)
+        return self.swiftTransaction.insertedObjectIDs(entity)
    }
    
    /**
@@ -163,7 +163,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func updatedObjectsOfType(_ entity: NSManagedObject.Type) -> Set<NSManagedObject> {
        
-        return self.bridgeToSwift.updatedObjects(entity)
+        return self.swiftTransaction.updatedObjects(entity)
    }
    
    /**
@@ -174,7 +174,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func updatedObjectIDs() -> Set<NSManagedObjectID> {
        
-        return self.bridgeToSwift.updatedObjectIDs()
+        return self.swiftTransaction.updatedObjectIDs()
    }
    
    /**
@@ -186,7 +186,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func updatedObjectIDsOfType(_ entity: NSManagedObject.Type) -> Set<NSManagedObjectID> {
        
-        return self.bridgeToSwift.updatedObjectIDs(entity)
+        return self.swiftTransaction.updatedObjectIDs(entity)
    }
    
    /**
@@ -198,7 +198,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func deletedObjectsOfType(_ entity: NSManagedObject.Type) -> Set<NSManagedObject> {
        
-        return self.bridgeToSwift.deletedObjects(entity)
+        return self.swiftTransaction.deletedObjects(entity)
    }
    
    /**
@@ -209,7 +209,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func deletedObjectIDs() -> Set<NSManagedObjectID> {
        
-        return self.bridgeToSwift.deletedObjectIDs()
+        return self.swiftTransaction.deletedObjectIDs()
    }

    /**
@@ -221,7 +221,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func deletedObjectIDsOfType(_ entity: NSManagedObject.Type) -> Set<NSManagedObjectID> {
        
-        return self.bridgeToSwift.deletedObjectIDs(entity)
+        return self.swiftTransaction.deletedObjectIDs(entity)
    }
    
    
@@ -229,7 +229,7 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    
    public override var hash: Int {
        
-        return ObjectIdentifier(self.bridgeToSwift).hashValue
+        return ObjectIdentifier(self.swiftTransaction).hashValue
    }
    
    public override func isEqual(_ object: Any?) -> Bool {
@@ -238,28 +238,20 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
            
            return false
        }
-        return self.bridgeToSwift === object.bridgeToSwift
+        return self.swiftTransaction === object.swiftTransaction
    }
    
    
-    // MARK: CoreStoreObjectiveCType
+    // MARK: Internal
    
-    public required init(_ swiftValue: BaseDataTransaction) {
+    internal let swiftTransaction: BaseDataTransaction
+    
+    internal init(_ swiftValue: BaseDataTransaction) {
        
        self.swiftTransaction = swiftValue
        super.init()
    }
    
-    public var bridgeToSwift: BaseDataTransaction {
-        
-        return self.swiftTransaction
-    }
-    
-    
-    // MARK: Private
-    
-    private let swiftTransaction: BaseDataTransaction
-    
    
    // MARK: Deprecated
    
@@ -267,20 +259,20 @@ public class CSBaseDataTransaction: NSObject, CoreStoreObjectiveCType {
    @objc
    public func insertedObjects() -> Set<NSManagedObject> {
        
-        return self.bridgeToSwift.insertedObjects()
+        return self.swiftTransaction.insertedObjects()
    }
    
    @available(*, deprecated, message: "Use -[updatedObjectsOfType:] and pass the specific entity class")
    @objc
    public func updatedObjects() -> Set<NSManagedObject> {
        
-        return self.bridgeToSwift.updatedObjects()
+        return self.swiftTransaction.updatedObjects()
    }
    
    @available(*, deprecated, message: "Use -[deletedObjectsOfType:] and pass the specific entity class")
    @objc
    public func deletedObjects() -> Set<NSManagedObject> {
        
-        return self.bridgeToSwift.deletedObjects()
+        return self.swiftTransaction.deletedObjects()
    }
 }
--- a/Sources/CSSynchronousDataTransaction.swift
+++ b/Sources/CSSynchronousDataTransaction.swift
@@ -35,7 +35,7 @@ import CoreData
 - SeeAlso: `SynchronousDataTransaction`
 */
@objc
-public final class CSSynchronousDataTransaction: CSBaseDataTransaction {
+public final class CSSynchronousDataTransaction: CSBaseDataTransaction, CoreStoreObjectiveCType {
    
    /**
     Saves the transaction changes and waits for completion synchronously. This method should not be used after the `-commitAndWaitWithError:` method was already called once.
@@ -129,9 +129,9 @@ public final class CSSynchronousDataTransaction: CSBaseDataTransaction {
    
    public typealias SwiftType = SynchronousDataTransaction
    
-    public override var bridgeToSwift: SynchronousDataTransaction {
+    public var bridgeToSwift: SynchronousDataTransaction {
        
-        return super.bridgeToSwift as! SynchronousDataTransaction
+        return super.swiftTransaction as! SynchronousDataTransaction
    }
    
    public required init(_ swiftValue: SynchronousDataTransaction) {
@@ -139,9 +139,9 @@ public final class CSSynchronousDataTransaction: CSBaseDataTransaction {
        super.init(swiftValue as BaseDataTransaction)
    }
    
-    public required init(_ swiftValue: BaseDataTransaction) {
+    public required override init(_ swiftValue: BaseDataTransaction) {
        
-        super.init(swiftValue as! SynchronousDataTransaction)
+        super.init(swiftValue)
    }
    
    
--- a/Sources/CSUnsafeDataTransaction.swift
+++ b/Sources/CSUnsafeDataTransaction.swift
@@ -35,7 +35,7 @@ import CoreData
 - SeeAlso: `UnsafeDataTransaction`
 */
@objc
-public final class CSUnsafeDataTransaction: CSBaseDataTransaction {
+public final class CSUnsafeDataTransaction: CSBaseDataTransaction, CoreStoreObjectiveCType {
    /**
     Saves the transaction changes asynchronously. For a `CSUnsafeDataTransaction`, multiple commits are allowed, although it is the developer's responsibility to ensure a reasonable leeway to prevent blocking the main thread.
     
@@ -189,9 +189,9 @@ public final class CSUnsafeDataTransaction: CSBaseDataTransaction {
    
    public typealias SwiftType = UnsafeDataTransaction
    
-    public override var bridgeToSwift: UnsafeDataTransaction {
+    public var bridgeToSwift: UnsafeDataTransaction {
        
-        return super.bridgeToSwift as! UnsafeDataTransaction
+        return super.swiftTransaction as! UnsafeDataTransaction
    }
    
    public required init(_ swiftValue: UnsafeDataTransaction) {
@@ -199,9 +199,9 @@ public final class CSUnsafeDataTransaction: CSBaseDataTransaction {
        super.init(swiftValue as BaseDataTransaction)
    }
    
-    public required init(_ swiftValue: BaseDataTransaction) {
+    public required override init(_ swiftValue: BaseDataTransaction) {
        
-        super.init(swiftValue as! UnsafeDataTransaction)
+        super.init(swiftValue)
    }
    
    
--- a/Sources/CoreStoreFetchedResultsController.swift
+++ b/Sources/CoreStoreFetchedResultsController.swift
@@ -35,7 +35,7 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
    // MARK: Internal
    
    @nonobjc
-    internal convenience init<T: DynamicObject>(dataStack: DataStack, fetchRequest: NSFetchRequest<NSManagedObject>, from: From<T>?, sectionBy: SectionBy? = nil, applyFetchClauses: @escaping (_ fetchRequest: NSFetchRequest<NSManagedObject>) -> Void) {
+    internal convenience init<T: DynamicObject>(dataStack: DataStack, fetchRequest: NSFetchRequest<NSManagedObject>, from: From<T>, sectionBy: SectionBy? = nil, applyFetchClauses: @escaping (_ fetchRequest: NSFetchRequest<NSManagedObject>) -> Void) {
        
        self.init(
            context: dataStack.mainContext,
@@ -47,33 +47,18 @@ internal final class CoreStoreFetchedResultsController: NSFetchedResultsControll
    }
    
    @nonobjc
-    internal init<T: DynamicObject>(context: NSManagedObjectContext, fetchRequest: NSFetchRequest<NSManagedObject>, from: From<T>?, sectionBy: SectionBy? = nil, applyFetchClauses: @escaping (_ fetchRequest: NSFetchRequest<NSManagedObject>) -> Void) {
+    internal init<T: DynamicObject>(context: NSManagedObjectContext, fetchRequest: NSFetchRequest<NSManagedObject>, from: From<T>, sectionBy: SectionBy? = nil, applyFetchClauses: @escaping (_ fetchRequest: NSFetchRequest<NSManagedObject>) -> Void) {
        
-        _ = from?.applyToFetchRequest(
+        _ = from.applyToFetchRequest(
            fetchRequest,
            context: context,
            applyAffectedStores: false
        )
        applyFetchClauses(fetchRequest)
        
-        if let from = from {
+        self.reapplyAffectedStores = { fetchRequest, context in
            
-            self.reapplyAffectedStores = { fetchRequest, context in
-                
-                return from.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
-            }
-        }
-        else {
-            
-            guard let from = (fetchRequest.entity.flatMap { $0.managedObjectClassName }).flatMap(NSClassFromString).flatMap({ From<T>($0 as! T.Type) }) else {
-                
-                CoreStore.abort("Attempted to create a \(CoreStoreFetchedResultsController.self) without a \(cs_typeName(From<T>.self)) clause or an \(cs_typeName(NSEntityDescription.self)).")
-            }
-            
-            self.reapplyAffectedStores = { fetchRequest, context in
-                
-                return from.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
-            }
+            return from.applyAffectedStoresForFetchedRequest(fetchRequest, context: context)
        }
        
        super.init(
--- a/Sources/CoreStoreManagedObject.swift
+++ b/Sources/CoreStoreManagedObject.swift
@@ -0,0 +1,34 @@
+//
+//  CoreStoreManagedObject.swift
+//  CoreStore
+//
+//  Created by John Rommel Estropia on 2017/06/04.
+//  Copyright © 2017 John Rommel Estropia. All rights reserved.
+//
+
+import CoreData
+
+
+// MARK: - CoreStoreManagedObject
+
+@objc internal class CoreStoreManagedObject: NSManagedObject {
+    
+    internal typealias CustomGetter = @convention(block) (_ rawObject: Any) -> Any?
+    internal typealias CustomSetter = @convention(block) (_ rawObject: Any, _ newValue: Any?) -> Void
+    internal typealias CustomGetterSetter = (getter: CustomGetter?, setter: CustomSetter?)
+    
+    @nonobjc @inline(__always)
+    internal static func cs_subclassName(for entity: DynamicEntity, in modelVersion: ModelVersion) -> String {
+        
+        return "_\(NSStringFromClass(CoreStoreManagedObject.self))__\(modelVersion)__\(NSStringFromClass(entity.type))__\(entity.entityName)"
+    }
+}
+
+
+// MARK: - Private
+
+private enum Static {
+    
+    static let queue = DispatchQueue.concurrent("com.coreStore.coreStoreManagerObjectBarrierQueue")
+    static var cache: [ObjectIdentifier: [KeyPath: Set<KeyPath>]] = [:]
+}
--- a/Sources/CoreStoreObject+Querying.swift
+++ b/Sources/CoreStoreObject+Querying.swift
@@ -53,6 +53,39 @@ public extension DynamicObject where Self: CoreStoreObject {
        return attribute(self.meta).keyPath
    }
    
+    /**
+     Extracts the keyPath string from a `CoreStoreObject.Relationship` property.
+     ```
+     let keyPath: String = Person.keyPath { $0.pets }
+     ```
+     */
+    public static func keyPath<O: CoreStoreObject, D: CoreStoreObject>(_ relationship: (Self) -> RelationshipContainer<O>.ToOne<D>) -> String  {
+        
+        return relationship(self.meta).keyPath
+    }
+    
+    /**
+     Extracts the keyPath string from a `CoreStoreObject.Relationship` property.
+     ```
+     let keyPath: String = Person.keyPath { $0.pets }
+     ```
+     */
+    public static func keyPath<O: CoreStoreObject, D: CoreStoreObject>(_ relationship: (Self) -> RelationshipContainer<O>.ToManyOrdered<D>) -> String  {
+        
+        return relationship(self.meta).keyPath
+    }
+    
+    /**
+     Extracts the keyPath string from a `CoreStoreObject.Relationship` property.
+     ```
+     let keyPath: String = Person.keyPath { $0.pets }
+     ```
+     */
+    public static func keyPath<O: CoreStoreObject, D: CoreStoreObject>(_ relationship: (Self) -> RelationshipContainer<O>.ToManyUnordered<D>) -> String  {
+        
+        return relationship(self.meta).keyPath
+    }
+    
    /**
     Creates a `Where` clause from a `CoreStoreObject.Value` property.
     ```
@@ -67,10 +100,10 @@ public extension DynamicObject where Self: CoreStoreObject {
    /**
     Creates an `OrderBy` clause from a `CoreStoreObject.Value` property.
     ```
-     let person = CoreStore.fetchAll(From<Person>(), Person.ascending { $0.age })
+     let person = CoreStore.fetchAll(From<Person>(), Person.orderBy(ascending: { $0.age }))
     ```
     */
-    public static func ascending<O: CoreStoreObject, V: ImportableAttributeType>(_ attribute: (Self) -> ValueContainer<O>.Optional<V>) -> OrderBy  {
+    public static func orderBy<O: CoreStoreObject, V: ImportableAttributeType>(ascending attribute: (Self) -> ValueContainer<O>.Required<V>) -> OrderBy  {
        
        return OrderBy(.ascending(attribute(self.meta).keyPath))
    }
@@ -78,9 +111,46 @@ public extension DynamicObject where Self: CoreStoreObject {
    /**
     Creates an `OrderBy` clause from a `CoreStoreObject.Value` property.
     ```
-     let person = CoreStore.fetchAll(From<Person>(), Person.descending { $0.age })
+     let person = CoreStore.fetchAll(From<Person>(), Person.orderBy(ascending: { $0.age }))
     ```
     */
+    public static func orderBy<O: CoreStoreObject, V: ImportableAttributeType>(ascending attribute: (Self) -> ValueContainer<O>.Optional<V>) -> OrderBy  {
+        
+        return OrderBy(.ascending(attribute(self.meta).keyPath))
+    }
+    
+    /**
+     Creates an `OrderBy` clause from a `CoreStoreObject.Value` property.
+     ```
+     let person = CoreStore.fetchAll(From<Person>(), Person.orderBy(descending: { $0.age }))
+     ```
+     */
+    public static func orderBy<O: CoreStoreObject, V: ImportableAttributeType>(descending attribute: (Self) -> ValueContainer<O>.Required<V>) -> OrderBy  {
+        
+        return OrderBy(.descending(attribute(self.meta).keyPath))
+    }
+    
+    /**
+     Creates an `OrderBy` clause from a `CoreStoreObject.Value` property.
+     ```
+     let person = CoreStore.fetchAll(From<Person>(), Person.orderBy(descending: { $0.age }))
+     ```
+     */
+    public static func orderBy<O: CoreStoreObject, V: ImportableAttributeType>(descending attribute: (Self) -> ValueContainer<O>.Optional<V>) -> OrderBy  {
+        
+        return OrderBy(.descending(attribute(self.meta).keyPath))
+    }
+    
+    
+    // MARK: Deprecated
+    
+    @available(*, deprecated, renamed: "orderBy(ascending:)")
+    public static func ascending<O: CoreStoreObject, V: ImportableAttributeType>(_ attribute: (Self) -> ValueContainer<O>.Optional<V>) -> OrderBy  {
+        
+        return OrderBy(.ascending(attribute(self.meta).keyPath))
+    }
+    
+    @available(*, deprecated, renamed: "orderBy(descending:)")
    public static func descending<O: CoreStoreObject, V: ImportableAttributeType>(_ attribute: (Self) -> ValueContainer<O>.Optional<V>) -> OrderBy  {
        
        return OrderBy(.descending(attribute(self.meta).keyPath))
@@ -163,6 +233,18 @@ public extension ValueContainer.Required {
        
        return Where("%K >= %@", attribute.keyPath, value)
    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Value` property.
+     ```
+     let dog = CoreStore.fetchOne(From<Dog>(), Dog.where { ["Pluto", "Snoopy", "Scooby"] ~= $0.nickname })
+     ```
+     */
+    @inline(__always)
+    public static func ~= <S: Sequence>(_ sequence: S, _ attribute: ValueContainer<O>.Required<V>) -> Where where S.Iterator.Element == V {
+        
+        return Where(attribute.keyPath, isMemberOf: sequence)
+    }
 }


@@ -193,4 +275,146 @@ public extension ValueContainer.Optional {
        
        return !Where(attribute.keyPath, isEqualTo: value)
    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Value` property.
+     ```
+     let person = CoreStore.fetchOne(From<Person>(), Person.where { $0.age < 20 })
+     ```
+     */
+    @inline(__always)
+    public static func < (_ attribute: ValueContainer<O>.Optional<V>, _ value: V?) -> Where {
+        
+        if let value = value {
+            
+            return Where("%K < %@", attribute.keyPath, value)
+        }
+        else {
+            
+            return Where("%K < nil", attribute.keyPath)
+        }
+    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Value` property.
+     ```
+     let person = CoreStore.fetchOne(From<Person>(), Person.where { $0.age > 20 })
+     ```
+     */
+    @inline(__always)
+    public static func > (_ attribute: ValueContainer<O>.Optional<V>, _ value: V?) -> Where {
+        
+        if let value = value {
+            
+            return Where("%K > %@", attribute.keyPath, value)
+        }
+        else {
+            
+            return Where("%K > nil", attribute.keyPath)
+        }
+    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Value` property.
+     ```
+     let person = CoreStore.fetchOne(From<Person>(), Person.where { $0.age <= 20 })
+     ```
+     */
+    @inline(__always)
+    public static func <= (_ attribute: ValueContainer<O>.Optional<V>, _ value: V?) -> Where {
+        
+        if let value = value {
+            
+            return Where("%K <= %@", attribute.keyPath, value)
+        }
+        else {
+            
+            return Where("%K <= nil", attribute.keyPath)
+        }
+    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Value` property.
+     ```
+     let person = CoreStore.fetchOne(From<Person>(), Person.where { $0.age >= 20 })
+     ```
+     */
+    @inline(__always)
+    public static func >= (_ attribute: ValueContainer<O>.Optional<V>, _ value: V?) -> Where {
+        
+        if let value = value {
+            
+            return Where("%K >= %@", attribute.keyPath, value)
+        }
+        else {
+            
+            return Where("%K >= nil", attribute.keyPath)
+        }
+    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Value` property.
+     ```
+     let dog = CoreStore.fetchOne(From<Dog>(), Dog.where { ["Pluto", "Snoopy", "Scooby"] ~= $0.nickname })
+     ```
+     */
+    @inline(__always)
+    public static func ~= <S: Sequence>(_ sequence: S, _ attribute: ValueContainer<O>.Optional<V>) -> Where where S.Iterator.Element == V {
+        
+        return Where(attribute.keyPath, isMemberOf: sequence)
+    }
+}
+
+
+// MARK: - RelationshipContainer.ToOne
+
+public extension RelationshipContainer.ToOne {
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Relationship` property.
+     ```
+     let dog = CoreStore.fetchOne(From<Dog>(), Dog.where { $0.master == me })
+     ```
+     */
+    @inline(__always)
+    public static func == (_ relationship: RelationshipContainer<O>.ToOne<D>, _ object: D?) -> Where {
+        
+        return Where(relationship.keyPath, isEqualTo: object)
+    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Relationship` property.
+     ```
+     let dog = CoreStore.fetchOne(From<Dog>(), Dog.where { $0.master != me })
+     ```
+     */
+    @inline(__always)
+    public static func != (_ relationship: RelationshipContainer<O>.ToOne<D>, _ object: D?) -> Where {
+        
+        return !Where(relationship.keyPath, isEqualTo: object)
+    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Relationship` property.
+     ```
+     let dog = CoreStore.fetchOne(From<Dog>(), Dog.where { $0.master ~= me })
+     ```
+     */
+    @inline(__always)
+    public static func ~= (_ relationship: RelationshipContainer<O>.ToOne<D>, _ object: D?) -> Where {
+        
+        return Where(relationship.keyPath, isEqualTo: object)
+    }
+    
+    /**
+     Creates a `Where` clause from a `CoreStoreObject.Relationship` property.
+     ```
+     let dog = CoreStore.fetchOne(From<Dog>(), Dog.where { [john, joe, bob] ~= $0.master })
+     ```
+     */
+    @inline(__always)
+    public static func ~= <S: Sequence>(_ sequence: S, _ relationship: RelationshipContainer<O>.ToOne<D>) -> Where where S.Iterator.Element == D {
+        
+        return Where(relationship.keyPath, isMemberOf: sequence)
+    }
 }
--- a/Sources/CoreStoreObject.swift
+++ b/Sources/CoreStoreObject.swift
@@ -68,8 +68,8 @@ open /*abstract*/ class CoreStoreObject: DynamicObject, Hashable {
    public required init(rawObject: NSManagedObject) {
        
        self.isMeta = false
-        self.rawObject = rawObject
-        self.initializeAttributes(Mirror(reflecting: self), { [unowned self] in self })
+        self.rawObject = (rawObject as! CoreStoreManagedObject)
+        self.initializeAttributes(Mirror(reflecting: self), self)
    }
    
    /**
@@ -110,13 +110,13 @@ open /*abstract*/ class CoreStoreObject: DynamicObject, Hashable {
    
    // MARK: Internal
    
-    internal let rawObject: NSManagedObject?
+    internal let rawObject: CoreStoreManagedObject?
    internal let isMeta: Bool
    
    
    // MARK: Private
    
-    private func initializeAttributes(_ mirror: Mirror, _ parentObject: @escaping () -> CoreStoreObject) {
+    private func initializeAttributes(_ mirror: Mirror, _ parentObject: CoreStoreObject) {
        
        _ = mirror.superclassMirror.flatMap({ self.initializeAttributes($0, parentObject) })
        for child in mirror.children {
--- a/Sources/CoreStoreSchema.swift
+++ b/Sources/CoreStoreSchema.swift
@@ -200,35 +200,44 @@ public final class CoreStoreSchema: DynamicSchema {
    
    public func rawModel() -> NSManagedObjectModel {
        
-        if let cachedRawModel = self.cachedRawModel {
+        return CoreStoreSchema.barrierQueue.sync(flags: .barrier) {
            
-            return cachedRawModel
-        }
-        let rawModel = NSManagedObjectModel()
-        var entityDescriptionsByEntity: [DynamicEntity: NSEntityDescription] = [:]
-        for entity in self.allEntities {
-            
-            let entityDescription = self.entityDescription(
-                for: entity,
-                initializer: CoreStoreSchema.firstPassCreateEntityDescription
+            if let cachedRawModel = self.cachedRawModel {
+                
+                return cachedRawModel
+            }
+            let rawModel = NSManagedObjectModel()
+            var entityDescriptionsByEntity: [DynamicEntity: NSEntityDescription] = [:]
+            var allCustomGettersSetters: [DynamicEntity: [KeyPath: CoreStoreManagedObject.CustomGetterSetter]] = [:]
+            for entity in self.allEntities {
+                
+                let (entityDescription, customGetterSetterByKeyPaths) = self.entityDescription(
+                    for: entity,
+                    initializer: CoreStoreSchema.firstPassCreateEntityDescription(from:in:)
+                )
+                entityDescriptionsByEntity[entity] = (entityDescription.copy() as! NSEntityDescription)
+                allCustomGettersSetters[entity] = customGetterSetterByKeyPaths
+            }
+            CoreStoreSchema.secondPassConnectRelationshipAttributes(for: entityDescriptionsByEntity)
+            CoreStoreSchema.thirdPassConnectInheritanceTree(for: entityDescriptionsByEntity)
+            CoreStoreSchema.fourthPassSynthesizeManagedObjectClasses(
+                for: entityDescriptionsByEntity,
+                allCustomGettersSetters: allCustomGettersSetters
            )
-            entityDescriptionsByEntity[entity] = (entityDescription.copy() as! NSEntityDescription)
-        }
-        CoreStoreSchema.secondPassConnectRelationshipAttributes(for: entityDescriptionsByEntity)
-        CoreStoreSchema.thirdPassConnectInheritanceTree(for: entityDescriptionsByEntity)
-        
-        rawModel.entities = entityDescriptionsByEntity.values.sorted(by: { $0.name! < $1.name! })
-        for (configuration, entities) in self.entitiesByConfiguration {
            
-            rawModel.setEntities(
-                entities
-                    .map({ entityDescriptionsByEntity[$0]! })
-                    .sorted(by: { $0.name! < $1.name! }),
-                forConfigurationName: configuration
-            )
+            rawModel.entities = entityDescriptionsByEntity.values.sorted(by: { $0.name! < $1.name! })
+            for (configuration, entities) in self.entitiesByConfiguration {
+                
+                rawModel.setEntities(
+                    entities
+                        .map({ entityDescriptionsByEntity[$0]! })
+                        .sorted(by: { $0.name! < $1.name! }),
+                    forConfigurationName: configuration
+                )
+            }
+            self.cachedRawModel = rawModel
+            return rawModel
        }
-        self.cachedRawModel = rawModel
-        return rawModel
    }
    
    
@@ -244,28 +253,33 @@ public final class CoreStoreSchema: DynamicSchema {
    private let allEntities: Set<DynamicEntity>
    
    private var entityDescriptionsByEntity: [DynamicEntity: NSEntityDescription] = [:]
+    private var customGettersSettersByEntity: [DynamicEntity: [KeyPath: CoreStoreManagedObject.CustomGetterSetter]] = [:]
    private weak var cachedRawModel: NSManagedObjectModel?
    
-    private func entityDescription(for entity: DynamicEntity, initializer: (DynamicEntity) -> NSEntityDescription) -> NSEntityDescription {
+    private func entityDescription(for entity: DynamicEntity, initializer: (DynamicEntity, ModelVersion) -> (entity: NSEntityDescription, customGetterSetterByKeyPaths: [KeyPath: CoreStoreManagedObject.CustomGetterSetter])) -> (entity: NSEntityDescription, customGetterSetterByKeyPaths: [KeyPath: CoreStoreManagedObject.CustomGetterSetter]) {
        
        if let cachedEntityDescription = self.entityDescriptionsByEntity[entity] {
            
-            return cachedEntityDescription
+            return (cachedEntityDescription, self.customGettersSettersByEntity[entity] ?? [:])
        }
-        let entityDescription = withoutActuallyEscaping(initializer, do: { $0(entity) })
+        let modelVersion = self.modelVersion
+        let (entityDescription, customGetterSetterByKeyPaths) = withoutActuallyEscaping(initializer, do: { $0(entity, modelVersion) })
        self.entityDescriptionsByEntity[entity] = entityDescription
-        return entityDescription
+        self.customGettersSettersByEntity[entity] = customGetterSetterByKeyPaths
+        return (entityDescription, customGetterSetterByKeyPaths)
    }
    
-    private static func firstPassCreateEntityDescription(from entity: DynamicEntity) -> NSEntityDescription {
+    private static func firstPassCreateEntityDescription(from entity: DynamicEntity, in modelVersion: ModelVersion) -> (entity: NSEntityDescription, customGetterSetterByKeyPaths: [KeyPath: CoreStoreManagedObject.CustomGetterSetter]) {
        
        let entityDescription = NSEntityDescription()
        entityDescription.coreStoreEntity = entity
        entityDescription.name = entity.entityName
        entityDescription.isAbstract = entity.isAbstract
        entityDescription.versionHashModifier = entity.versionHashModifier
-        entityDescription.managedObjectClassName = NSStringFromClass(NSManagedObject.self)
+        entityDescription.managedObjectClassName = CoreStoreManagedObject.cs_subclassName(for: entity, in: modelVersion)
        
+        var keyPathsByAffectedKeyPaths: [KeyPath: Set<KeyPath>] = [:]
+        var customGetterSetterByKeyPaths: [KeyPath: CoreStoreManagedObject.CustomGetterSetter] = [:]
        func createProperties(for type: CoreStoreObject.Type) -> [NSPropertyDescription] {
            
            var propertyDescriptions: [NSPropertyDescription] = []
@@ -279,11 +293,13 @@ public final class CoreStoreSchema: DynamicSchema {
                    description.attributeType = type(of: attribute).attributeType
                    description.isOptional = attribute.isOptional
                    description.isIndexed = attribute.isIndexed
-                    description.defaultValue = attribute.defaultValue
+                    description.defaultValue = attribute.defaultValue()
                    description.isTransient = attribute.isTransient
                    description.versionHashModifier = attribute.versionHashModifier
                    description.renamingIdentifier = attribute.renamingIdentifier
                    propertyDescriptions.append(description)
+                    keyPathsByAffectedKeyPaths[attribute.keyPath] = attribute.affectedByKeyPaths()
+                    customGetterSetterByKeyPaths[attribute.keyPath] = (attribute.getter, attribute.setter)
                    
                case let relationship as RelationshipProtocol:
                    let description = NSRelationshipDescription()
@@ -295,6 +311,7 @@ public final class CoreStoreSchema: DynamicSchema {
                    description.versionHashModifier = relationship.versionHashModifier
                    description.renamingIdentifier = relationship.renamingIdentifier
                    propertyDescriptions.append(description)
+                    keyPathsByAffectedKeyPaths[relationship.keyPath] = relationship.affectedByKeyPaths()
                    
                default:
                    continue
@@ -302,9 +319,9 @@ public final class CoreStoreSchema: DynamicSchema {
            }
            return propertyDescriptions
        }
-        
        entityDescription.properties = createProperties(for: entity.type as! CoreStoreObject.Type)
-        return entityDescription
+        entityDescription.keyPathsByAffectedKeyPaths = keyPathsByAffectedKeyPaths
+        return (entityDescription, customGetterSetterByKeyPaths)
    }
    
    private static func secondPassConnectRelationshipAttributes(for entityDescriptionsByEntity: [DynamicEntity: NSEntityDescription]) {
@@ -425,4 +442,112 @@ public final class CoreStoreSchema: DynamicSchema {
            )
        }
    }
+    
+    private static func fourthPassSynthesizeManagedObjectClasses(for entityDescriptionsByEntity: [DynamicEntity: NSEntityDescription], allCustomGettersSetters: [DynamicEntity: [KeyPath: CoreStoreManagedObject.CustomGetterSetter]]) {
+        
+        func createManagedObjectSubclass(for entityDescription: NSEntityDescription, customGetterSetterByKeyPaths: [KeyPath: CoreStoreManagedObject.CustomGetterSetter]?) {
+            
+            let superEntity = entityDescription.superentity
+            let className = entityDescription.managedObjectClassName!
+            guard case nil = NSClassFromString(className) as! CoreStoreManagedObject.Type? else {
+                
+                return
+            }
+            if let superEntity = superEntity {
+                
+                createManagedObjectSubclass(
+                    for: superEntity,
+                    customGetterSetterByKeyPaths: superEntity.coreStoreEntity.flatMap({ allCustomGettersSetters[$0] })
+                )
+            }
+            let superClass = cs_lazy { () -> CoreStoreManagedObject.Type in
+                
+                if let superClassName = superEntity?.managedObjectClassName,
+                    let superClass = NSClassFromString(superClassName) {
+                    
+                    return superClass as! CoreStoreManagedObject.Type
+                }
+                return CoreStoreManagedObject.self
+            }
+            let managedObjectClass: AnyClass = className.withCString {
+                
+                return objc_allocateClassPair(superClass, $0, 0)!
+            }
+            defer {
+            
+                objc_registerClassPair(managedObjectClass)
+            }
+            
+            func capitalize(_ string: String) -> String {
+                
+                return string.replacingCharacters(
+                    in: Range(uncheckedBounds: (string.startIndex, string.index(after: string.startIndex))),
+                    with: String(string[string.startIndex]).uppercased()
+                )
+            }
+            for (attributeName, customGetterSetters) in (customGetterSetterByKeyPaths ?? [:])
+                where customGetterSetters.getter != nil || customGetterSetters.setter != nil {
+                    
+                    if let getter = customGetterSetters.getter {
+                        
+                        let getterName = "\(attributeName)"
+                        guard class_addMethod(
+                            managedObjectClass,
+                            NSSelectorFromString(getterName),
+                            imp_implementationWithBlock(getter),
+                            "@@:") else {
+                                
+                                CoreStore.abort("Could not dynamically add getter method \"\(getterName)\" to class \(cs_typeName(managedObjectClass))")
+                        }
+                    }
+                    if let setter = customGetterSetters.setter {
+                        
+                        let setterName = "set\(capitalize(attributeName)):"
+                        guard class_addMethod(
+                            managedObjectClass,
+                            NSSelectorFromString(setterName),
+                            imp_implementationWithBlock(setter),
+                            "v@:@") else {
+                                
+                                CoreStore.abort("Could not dynamically add setter method \"\(setterName)\" to class \(cs_typeName(managedObjectClass))")
+                        }
+                    }
+            }
+            
+            let newSelector = NSSelectorFromString("cs_keyPathsForValuesAffectingValueForKey:")
+            let keyPathsByAffectedKeyPaths = entityDescription.keyPathsByAffectedKeyPaths
+            let keyPathsForValuesAffectingValue: @convention(block) (Any, String) -> Set<String> = { (instance, keyPath) in
+                
+                if let keyPaths = keyPathsByAffectedKeyPaths[keyPath] {
+                    
+                    return keyPaths
+                }
+                return []
+            }
+            let origSelector = #selector(NSManagedObject.keyPathsForValuesAffectingValue(forKey:))
+            
+            let metaClass: AnyClass = object_getClass(managedObjectClass)!
+            let origMethod = class_getClassMethod(managedObjectClass, origSelector)
+            
+            let origImp = method_getImplementation(origMethod)
+            let newImp = imp_implementationWithBlock(keyPathsForValuesAffectingValue)
+            
+            if class_addMethod(metaClass, origSelector, newImp, method_getTypeEncoding(origMethod)) {
+                
+                class_replaceMethod(metaClass, newSelector, origImp, method_getTypeEncoding(origMethod))
+            }
+            else {
+                
+                let newMethod = class_getClassMethod(managedObjectClass, newSelector)
+                method_exchangeImplementations(origMethod, newMethod)
+            }
+        }
+        for (dynamicEntity, entityDescription) in entityDescriptionsByEntity {
+            
+            createManagedObjectSubclass(
+                for: entityDescription,
+                customGetterSetterByKeyPaths: allCustomGettersSetters[dynamicEntity]
+            )
+        }
+    }
 }
--- a/Sources/CustomSchemaMappingProvider.swift
+++ b/Sources/CustomSchemaMappingProvider.swift
@@ -32,7 +32,7 @@ import Foundation
 /**
 A `SchemaMappingProvider` that accepts custom mappings for some entities. Mappings of entities with no `CustomMapping` provided will be automatically calculated if possible.
 */
-open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
+public class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
    
    /**
     The source model version for the mapping.
@@ -352,7 +352,7 @@ open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
        )
        func expression(forSource sourceEntity: NSEntityDescription) -> NSExpression {
            
-            return NSExpression(format: "FETCH(FUNCTION($\(NSMigrationManagerKey), \"fetchRequestForSourceEntityNamed:predicateString:\" , \"\(sourceEntity.name!)\", \"\(NSPredicate(value: true))\"), $\(NSMigrationManagerKey).\(#keyPath(NSMigrationManager.sourceContext)), \(false))")
+            return NSExpression(format: "FETCH(FUNCTION($\(NSMigrationManagerKey), \"fetchRequestForSourceEntityNamed:predicateString:\" , \"\(sourceEntity.name!)\", \"\(NSPredicate(value: true))\"), FUNCTION($\(NSMigrationManagerKey), \"\(#selector(getter: NSMigrationManager.sourceContext))\"), \(false))")
        }
        
        let sourceEntitiesByName = sourceModel.entitiesByName
@@ -427,22 +427,25 @@ open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
                    let destinationAttribute = destination.attribute
                    let propertyMapping = NSPropertyMapping()
                    propertyMapping.name = destinationAttribute.name
-                    propertyMapping.valueExpression = NSExpression(format: "$\(NSMigrationSourceObjectKey).\(sourceAttribute.name)")
+                    propertyMapping.valueExpression = NSExpression(format: "FUNCTION($\(NSMigrationSourceObjectKey), \"\(#selector(NSManagedObject.value(forKey:)))\", \"\(sourceAttribute.name)\")")
                    attributeMappings.append(propertyMapping)
                }
                return attributeMappings
            }
-            let entityMappingName = entityMapping.name!
            entityMapping.relationshipMappings = autoreleasepool { () -> [NSPropertyMapping] in
                
+                let sourceRelationships = sourceEntity.cs_resolvedRelationshipRenamingIdentities()
                let destinationRelationships = destinationEntity.cs_resolvedRelationshipRenamingIdentities()
                var relationshipMappings: [NSPropertyMapping] = []
-                for (_, destination) in destinationRelationships {
+                for (renamingIdentifier, destination) in destinationRelationships {
                    
+                    let sourceRelationship = sourceRelationships[renamingIdentifier]!.relationship
                    let destinationRelationship = destination.relationship
+                    let sourceRelationshipName = sourceRelationship.name
+
                    let propertyMapping = NSPropertyMapping()
                    propertyMapping.name = destinationRelationship.name
-                    propertyMapping.valueExpression = NSExpression(format: "FUNCTION($\(NSMigrationManagerKey), \"\(#selector(NSMigrationManager.destinationInstances(forEntityMappingName:sourceInstances:)))\" , \"\(entityMappingName)\", $\(NSMigrationSourceObjectKey))[0]")
+                    propertyMapping.valueExpression = NSExpression(format: "FUNCTION($\(NSMigrationManagerKey), \"destinationInstancesForSourceRelationshipNamed:sourceInstances:\", \"\(sourceRelationshipName)\", FUNCTION($\(NSMigrationSourceObjectKey), \"\(#selector(NSManagedObject.value(forKey:)))\", \"\(sourceRelationshipName)\"))")
                    relationshipMappings.append(propertyMapping)
                }
                return relationshipMappings
@@ -483,17 +486,24 @@ open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
                }
                userInfo[CustomEntityMigrationPolicy.UserInfoKey.sourceAttributesByDestinationKey] = sourceAttributesByDestinationKey
            }
-            let entityMappingName = entityMapping.name!
            entityMapping.relationshipMappings = autoreleasepool { () -> [NSPropertyMapping] in
                
+                let sourceRelationships = sourceEntity.cs_resolvedRelationshipRenamingIdentities()
                let destinationRelationships = destinationEntity.cs_resolvedRelationshipRenamingIdentities()
+                let transformedRenamingIdentifiers = Set(destinationRelationships.keys)
+                    .intersection(sourceRelationships.keys)
+
                var relationshipMappings: [NSPropertyMapping] = []
-                for (_, destination) in destinationRelationships {
-                    
-                    let destinationRelationship = destination.relationship
+                for renamingIdentifier in transformedRenamingIdentifiers {
+
+                    let sourceRelationship = sourceRelationships[renamingIdentifier]!.relationship
+                    let destinationRelationship = destinationRelationships[renamingIdentifier]!.relationship
+                    let sourceRelationshipName = sourceRelationship.name
+                    let destinationRelationshipName = destinationRelationship.name
+
                    let propertyMapping = NSPropertyMapping()
-                    propertyMapping.name = destinationRelationship.name
-                    propertyMapping.valueExpression = NSExpression(format: "FUNCTION($\(NSMigrationManagerKey), \"\(#selector(NSMigrationManager.destinationInstances(forEntityMappingName:sourceInstances:)))\" , \"\(entityMappingName)\", $\(NSMigrationSourceObjectKey))[0]")
+                    propertyMapping.name = destinationRelationshipName
+                    propertyMapping.valueExpression = NSExpression(format: "FUNCTION($\(NSMigrationManagerKey), \"destinationInstancesForSourceRelationshipNamed:sourceInstances:\", \"\(sourceRelationshipName)\", FUNCTION($\(NSMigrationSourceObjectKey), \"\(#selector(NSManagedObject.value(forKey:)))\", \"\(sourceRelationshipName)\"))")
                    relationshipMappings.append(propertyMapping)
                }
                return relationshipMappings
@@ -545,11 +555,7 @@ open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
            )
            if let dInstance = destinationObject?.rawObject {
                
-                manager.associate(
-                    sourceInstance: sInstance,
-                    withDestinationInstance: dInstance,
-                    for: mapping
-                )
+                manager.associate(sourceInstance: sInstance, withDestinationInstance: dInstance, for: mapping)
            }
        }
        
@@ -670,77 +676,76 @@ open class CustomSchemaMappingProvider: Hashable, SchemaMappingProvider {
                allMappedSourceKeys[sourceEntity] = destinationEntity
                allMappedDestinationKeys[destinationEntity] = sourceEntity
            }
+        }
+        for renamingIdentifier in transformedRenamingIdentifiers {
            
-            for renamingIdentifier in transformedRenamingIdentifiers {
+            let sourceEntity = sourceRenamingIdentifiers[renamingIdentifier]!.entity
+            let destinationEntity = destinationRenamingIdentifiers[renamingIdentifier]!.entity
+            let sourceEntityName = sourceEntity.name!
+            let destinationEntityName = destinationEntity.name!
+            switch (allMappedSourceKeys[sourceEntityName], allMappedDestinationKeys[destinationEntityName]) {
                
-                let sourceEntity = sourceRenamingIdentifiers[renamingIdentifier]!.entity
-                let destinationEntity = destinationRenamingIdentifiers[renamingIdentifier]!.entity
-                let sourceEntityName = sourceEntity.name!
-                let destinationEntityName = destinationEntity.name!
-                switch (allMappedSourceKeys[sourceEntityName], allMappedDestinationKeys[destinationEntityName]) {
+            case (nil, nil):
+                if sourceEntity.versionHash == destinationEntity.versionHash {
                    
-                case (nil, nil):
-                    if sourceEntity.versionHash == destinationEntity.versionHash {
-                        
-                        copyMappings.insert(
-                            .copyEntity(
-                                sourceEntity: sourceEntityName,
-                                destinationEntity: destinationEntityName
-                            )
+                    copyMappings.insert(
+                        .copyEntity(
+                            sourceEntity: sourceEntityName,
+                            destinationEntity: destinationEntityName
                        )
-                    }
-                    else {
-                        
-                        transformMappings.insert(
-                            .transformEntity(
-                                sourceEntity: sourceEntityName,
-                                destinationEntity: destinationEntityName,
-                                transformer: CustomMapping.inferredTransformation
-                            )
+                    )
+                }
+                else {
+                    
+                    transformMappings.insert(
+                        .transformEntity(
+                            sourceEntity: sourceEntityName,
+                            destinationEntity: destinationEntityName,
+                            transformer: CustomMapping.inferredTransformation
                        )
-                    }
-                    allMappedSourceKeys[sourceEntityName] = destinationEntityName
-                    allMappedDestinationKeys[destinationEntityName] = sourceEntityName
-                    
-                case (""?, nil):
-                    insertMappings.insert(.insertEntity(destinationEntity: destinationEntityName))
-                    allMappedDestinationKeys[destinationEntityName] = ""
-                    
-                case (nil, ""?):
-                    deleteMappings.insert(.deleteEntity(sourceEntity: sourceEntityName))
-                    allMappedSourceKeys[sourceEntityName] = ""
-                    
-                default:
-                    continue
+                    )
                }
-            }
-            for renamingIdentifier in removedRenamingIdentifiers {
+                allMappedSourceKeys[sourceEntityName] = destinationEntityName
+                allMappedDestinationKeys[destinationEntityName] = sourceEntityName
                
-                let sourceEntity = sourceRenamingIdentifiers[renamingIdentifier]!.entity
-                let sourceEntityName = sourceEntity.name!
-                switch allMappedSourceKeys[sourceEntityName] {
-                    
-                case nil:
-                    deleteMappings.insert(.deleteEntity(sourceEntity: sourceEntityName))
-                    allMappedSourceKeys[sourceEntityName] = ""
-                    
-                default:
-                    continue
-                }
-            }
-            for renamingIdentifier in addedRenamingIdentifiers {
+            case (""?, nil):
+                insertMappings.insert(.insertEntity(destinationEntity: destinationEntityName))
+                allMappedDestinationKeys[destinationEntityName] = ""
                
-                let destinationEntity = destinationRenamingIdentifiers[renamingIdentifier]!.entity
-                let destinationEntityName = destinationEntity.name!
-                switch allMappedDestinationKeys[destinationEntityName] {
-                    
-                case nil:
-                    insertMappings.insert(.insertEntity(destinationEntity: destinationEntityName))
-                    allMappedDestinationKeys[destinationEntityName] = ""
-                    
-                default:
-                    continue
-                }
+            case (nil, ""?):
+                deleteMappings.insert(.deleteEntity(sourceEntity: sourceEntityName))
+                allMappedSourceKeys[sourceEntityName] = ""
+                
+            default:
+                continue
+            }
+        }
+        for renamingIdentifier in removedRenamingIdentifiers {
+            
+            let sourceEntity = sourceRenamingIdentifiers[renamingIdentifier]!.entity
+            let sourceEntityName = sourceEntity.name!
+            switch allMappedSourceKeys[sourceEntityName] {
+                
+            case nil:
+                deleteMappings.insert(.deleteEntity(sourceEntity: sourceEntityName))
+                allMappedSourceKeys[sourceEntityName] = ""
+                
+            default:
+                continue
+            }
+        }
+        for renamingIdentifier in addedRenamingIdentifiers {
+            
+            let destinationEntity = destinationRenamingIdentifiers[renamingIdentifier]!.entity
+            let destinationEntityName = destinationEntity.name!
+            switch allMappedDestinationKeys[destinationEntityName] {
+                
+            case nil:
+                insertMappings.insert(.insertEntity(destinationEntity: destinationEntityName))
+                allMappedDestinationKeys[destinationEntityName] = ""
+                
+            default:
+                continue
            }
        }
        return (deleteMappings, insertMappings, copyMappings, transformMappings)
--- a/Sources/InferredSchemaMappingProvider.swift
+++ b/Sources/InferredSchemaMappingProvider.swift
@@ -32,7 +32,7 @@ import Foundation
 /**
 A `SchemaMappingProvider` that tries to infer model migration between two `DynamicSchema` versions by searching all `xcmappingmodel`s from `Bundle.allBundles` or by relying on lightweight migration if possible. Throws an error if lightweight migration is impossible for the two `DynamicSchema`. This mapping is automatically used as a fallback mapping provider, even if no mapping providers are explicitly declared in the `StorageInterface`.
 */
-final class InferredSchemaMappingProvider: Hashable, SchemaMappingProvider {
+public final class InferredSchemaMappingProvider: Hashable, SchemaMappingProvider {
    
    // MARK: Equatable
    
--- a/Sources/Info.plist
+++ b/Sources/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>4.0.0</string>
+	<string>4.0.5</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
--- a/Sources/ListMonitor.swift
+++ b/Sources/ListMonitor.swift
@@ -704,13 +704,13 @@ public final class ListMonitor<D: DynamicObject>: Hashable {
                    
                    guard let `self` = self,
                        let userInfo = note.userInfo,
-                        let object = userInfo[String(describing: NSManagedObject.self)] as? ObjectType else {
+                        let rawObject = userInfo[String(describing: NSManagedObject.self)] as? NSManagedObject else {
                            
                            return
                    }
                    callback(
                        self,
-                        object,
+                        ObjectType.cs_fromRaw(object: rawObject),
                        userInfo[String(describing: IndexPath.self)] as? IndexPath,
                        userInfo["\(String(describing: IndexPath.self)).New"] as? IndexPath
                    )
--- a/Sources/NSEntityDescription+DynamicModel.swift
+++ b/Sources/NSEntityDescription+DynamicModel.swift
@@ -54,17 +54,65 @@ internal extension NSEntityDescription {
            
            if let newValue = newValue {
                
-                var userInfo: [AnyHashable : Any] = [
-                    UserInfoKey.CoreStoreManagedObjectTypeName: NSStringFromClass(newValue.type),
-                    UserInfoKey.CoreStoreManagedObjectEntityName: newValue.entityName,
-                    UserInfoKey.CoreStoreManagedObjectIsAbstract: newValue.isAbstract
-                ]
-                userInfo[UserInfoKey.CoreStoreManagedObjectVersionHashModifier] = newValue.versionHashModifier
-                self.userInfo = userInfo
+                cs_setUserInfo { (userInfo) in
+                    
+                    userInfo[UserInfoKey.CoreStoreManagedObjectTypeName] = NSStringFromClass(newValue.type)
+                    userInfo[UserInfoKey.CoreStoreManagedObjectEntityName] = newValue.entityName
+                    userInfo[UserInfoKey.CoreStoreManagedObjectIsAbstract] = newValue.isAbstract
+                    userInfo[UserInfoKey.CoreStoreManagedObjectVersionHashModifier] = newValue.versionHashModifier
+                }
            }
            else {
                
-                self.userInfo = [:]
+                cs_setUserInfo { (userInfo) in
+                    
+                    userInfo[UserInfoKey.CoreStoreManagedObjectTypeName] = nil
+                    userInfo[UserInfoKey.CoreStoreManagedObjectEntityName] = nil
+                    userInfo[UserInfoKey.CoreStoreManagedObjectIsAbstract] = nil
+                    userInfo[UserInfoKey.CoreStoreManagedObjectVersionHashModifier] = nil
+                }
+            }
+        }
+    }
+    
+    @nonobjc
+    internal var keyPathsByAffectedKeyPaths: [KeyPath: Set<KeyPath>] {
+        
+        get {
+            
+            if let userInfo = self.userInfo,
+                let value = userInfo[UserInfoKey.CoreStoreManagedObjectKeyPathsByAffectedKeyPaths] {
+                
+                return value as! [KeyPath: Set<KeyPath>]
+            }
+            return [:]
+        }
+        set {
+            
+            cs_setUserInfo { (userInfo) in
+                
+                userInfo[UserInfoKey.CoreStoreManagedObjectKeyPathsByAffectedKeyPaths] = newValue
+            }
+        }
+    }
+    
+    @nonobjc
+    internal var customGetterSetterByKeyPaths: [KeyPath: CoreStoreManagedObject.CustomGetterSetter] {
+        
+        get {
+            
+            if let userInfo = self.userInfo,
+                let value = userInfo[UserInfoKey.CoreStoreManagedObjectCustomGetterSetterByKeyPaths] {
+                
+                return value as! [KeyPath: CoreStoreManagedObject.CustomGetterSetter]
+            }
+            return [:]
+        }
+        set {
+            
+            cs_setUserInfo { (userInfo) in
+                
+                userInfo[UserInfoKey.CoreStoreManagedObjectCustomGetterSetterByKeyPaths] = newValue
            }
        }
    }
@@ -74,11 +122,22 @@ internal extension NSEntityDescription {
    
    // MARK: - UserInfoKey
    
-    fileprivate enum UserInfoKey {
+    private enum UserInfoKey {
        
        fileprivate static let CoreStoreManagedObjectTypeName = "CoreStoreManagedObjectTypeName"
        fileprivate static let CoreStoreManagedObjectEntityName = "CoreStoreManagedObjectEntityName"
        fileprivate static let CoreStoreManagedObjectIsAbstract = "CoreStoreManagedObjectIsAbstract"
        fileprivate static let CoreStoreManagedObjectVersionHashModifier = "CoreStoreManagedObjectVersionHashModifier"
+        
+        fileprivate static let CoreStoreManagedObjectKeyPathsByAffectedKeyPaths = "CoreStoreManagedObjectKeyPathsByAffectedKeyPaths"
+        fileprivate static let CoreStoreManagedObjectCustomGetterSetterByKeyPaths = "CoreStoreManagedObjectCustomGetterSetterByKeyPaths"
+        
+    }
+    
+    private func cs_setUserInfo(_ closure: (_ userInfo: inout [AnyHashable: Any]) -> Void) {
+        
+        var userInfo = self.userInfo ?? [:]
+        closure(&userInfo)
+        self.userInfo = userInfo
    }
 }
--- a/Sources/NSFetchedResultsController+Convenience.swift
+++ b/Sources/NSFetchedResultsController+Convenience.swift
@@ -201,7 +201,7 @@ public extension UnsafeDataTransaction {
 // MARK: - Private

@available(OSX 10.12, *)
-fileprivate func createFRC<T: NSManagedObject>(fromContext context: NSManagedObjectContext, from: From<T>? = nil, sectionBy: SectionBy? = nil, fetchClauses: [FetchClause]) -> NSFetchedResultsController<T> {
+fileprivate func createFRC<T: NSManagedObject>(fromContext context: NSManagedObjectContext, from: From<T>, sectionBy: SectionBy? = nil, fetchClauses: [FetchClause]) -> NSFetchedResultsController<T> {
    
    let controller = CoreStoreFetchedResultsController(
        context: context,
--- a/Sources/NSFetchedResultsController+ObjectiveC.swift
+++ b/Sources/NSFetchedResultsController+ObjectiveC.swift
@@ -68,12 +68,12 @@ public extension CSUnsafeDataTransaction {
 // MARK: - Private

@available(OSX 10.12, *)
-fileprivate func createFRC(fromContext context: NSManagedObjectContext, from: CSFrom? = nil, sectionBy: CSSectionBy?, fetchClauses: [CSFetchClause]) -> NSFetchedResultsController<NSManagedObject> {
+fileprivate func createFRC(fromContext context: NSManagedObjectContext, from: CSFrom, sectionBy: CSSectionBy?, fetchClauses: [CSFetchClause]) -> NSFetchedResultsController<NSManagedObject> {
    
    let controller = CoreStoreFetchedResultsController(
        context: context,
        fetchRequest: CoreStoreFetchRequest().dynamicCast(),
-        from: from?.bridgeToSwift,
+        from: from.bridgeToSwift,
        sectionBy: sectionBy?.bridgeToSwift,
        applyFetchClauses: { (fetchRequest) in
            
--- a/Sources/ObjectMonitor.swift
+++ b/Sources/ObjectMonitor.swift
@@ -272,7 +272,7 @@ public final class ObjectMonitor<D: DynamicObject>: Equatable {
        let fetchedResultsController = CoreStoreFetchedResultsController(
            context: context,
            fetchRequest: fetchRequest.dynamicCast(),
-            from: nil as From<ObjectType>?,
+            from: From<ObjectType>([objectID.persistentStore?.configurationName]),
            applyFetchClauses: Where("SELF", isEqualTo: objectID).applyToFetchRequest
        )
        
--- a/Sources/Relationship.swift
+++ b/Sources/Relationship.swift
@@ -92,10 +92,23 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { nil }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { nil },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -113,10 +126,24 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, inverse: @escaping (D) -> RelationshipContainer<D>.ToOne<O>, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToOne<O>,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -134,10 +161,24 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, inverse: @escaping (D) -> RelationshipContainer<D>.ToManyOrdered<O>, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToManyOrdered<O>,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -155,10 +196,24 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, inverse: @escaping (D) -> RelationshipContainer<D>.ToManyUnordered<O>, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToManyUnordered<O>,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -189,54 +244,64 @@ public enum RelationshipContainer<O: CoreStoreObject> {
        internal let inverse: (type: CoreStoreObject.Type, keyPath: () -> KeyPath?)
        internal let versionHashModifier: String?
        internal let renamingIdentifier: String?
-        
-        internal var parentObject: () -> CoreStoreObject = {
-            
-            CoreStore.abort("Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types.")
-        }
+        internal let affectedByKeyPaths: () -> Set<String>
+        internal weak var parentObject: CoreStoreObject?
        
        internal var nativeValue: NSManagedObject? {
            
            get {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                return object.rawObject!.getValue(
-                    forKvcKey: self.keyPath,
-                    didGetValue: { $0 as! NSManagedObject? }
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    return object.rawObject!.getValue(
+                        forKvcKey: self.keyPath,
+                        didGetValue: { $0 as! NSManagedObject? }
+                    )
+                }
            }
            set {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                CoreStore.assert(
-                    object.rawObject!.isEditableInContext() == true,
-                    "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
-                )
-                object.rawObject!.setValue(
-                    newValue,
-                    forKvcKey: self.keyPath
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    )
+                    object.rawObject!.setValue(
+                        newValue,
+                        forKvcKey: self.keyPath
+                    )
+                }
            }
        }
        
        
        // MARK: Private
        
-        private init(keyPath: KeyPath, inverseKeyPath: @escaping () -> KeyPath?, deleteRule: DeleteRule, versionHashModifier: String?, renamingIdentifier: String?) {
+        private init(keyPath: KeyPath, inverseKeyPath: @escaping () -> KeyPath?, deleteRule: DeleteRule, versionHashModifier: String?, renamingIdentifier: String?, affectedByKeyPaths: @autoclosure @escaping () -> Set<String>) {
            
            self.keyPath = keyPath
            self.deleteRule = deleteRule.nativeValue
            self.inverse = (D.self, inverseKeyPath)
            self.versionHashModifier = versionHashModifier
            self.renamingIdentifier = renamingIdentifier
+            self.affectedByKeyPaths = affectedByKeyPaths
        }
    }
    
@@ -273,10 +338,27 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, minCount: Int = 0, maxCount: Int = 0, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, minCount: minCount, maxCount: maxCount, inverseKeyPath: { nil }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                minCount: minCount,
+                maxCount: maxCount,
+                inverseKeyPath: { nil },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -296,10 +378,28 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, minCount: Int = 0, maxCount: Int = 0, inverse: @escaping (D) -> RelationshipContainer<D>.ToOne<O>, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToOne<O>,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, minCount: minCount, maxCount: maxCount, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                minCount: minCount,
+                maxCount: maxCount,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -319,10 +419,28 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, minCount: Int = 0, maxCount: Int = 0, inverse: @escaping (D) -> RelationshipContainer<D>.ToManyOrdered<O>, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToManyOrdered<O>,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, minCount: minCount, maxCount: maxCount, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                minCount: minCount,
+                maxCount: maxCount,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -342,10 +460,28 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, minCount: Int = 0, maxCount: Int = 0, inverse: @escaping (D) -> RelationshipContainer<D>.ToManyUnordered<O>, deleteRule: DeleteRule = .nullify, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToManyUnordered<O>,
+            deleteRule: DeleteRule = .nullify,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, minCount: minCount, maxCount: maxCount, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                minCount: minCount,
+                maxCount: maxCount,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -377,48 +513,57 @@ public enum RelationshipContainer<O: CoreStoreObject> {
        internal let inverse: (type: CoreStoreObject.Type, keyPath: () -> KeyPath?)
        internal let versionHashModifier: String?
        internal let renamingIdentifier: String?
-        
-        internal var parentObject: () -> CoreStoreObject = {
-            
-            CoreStore.abort("Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types.")
-        }
+        internal let affectedByKeyPaths: () -> Set<String>
+        internal weak var parentObject: CoreStoreObject?
        
        internal var nativeValue: NSOrderedSet {
            
            get {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                return object.rawObject!.getValue(
-                    forKvcKey: self.keyPath,
-                    didGetValue: { ($0 as! NSOrderedSet?) ?? [] }
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    return object.rawObject!.getValue(
+                        forKvcKey: self.keyPath,
+                        didGetValue: { ($0 as! NSOrderedSet?) ?? [] }
+                    )
+                }
            }
            set {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                CoreStore.assert(
-                    object.rawObject!.isEditableInContext() == true,
-                    "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
-                )
-                object.rawObject!.setValue(
-                    newValue,
-                    forKvcKey: self.keyPath
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    )
+                    object.rawObject!.setValue(
+                        newValue,
+                        forKvcKey: self.keyPath
+                    )
+                }
            }
        }
        
        
        // MARK: Private
        
-        private init(keyPath: String, minCount: Int, maxCount: Int, inverseKeyPath: @escaping () -> String?, deleteRule: DeleteRule, versionHashModifier: String?, renamingIdentifier: String?) {
+        private init(keyPath: String, minCount: Int, maxCount: Int, inverseKeyPath: @escaping () -> String?, deleteRule: DeleteRule, versionHashModifier: String?, renamingIdentifier: String?, affectedByKeyPaths: @autoclosure @escaping () -> Set<String>) {
            
            self.keyPath = keyPath
            self.deleteRule = deleteRule.nativeValue
@@ -429,6 +574,7 @@ public enum RelationshipContainer<O: CoreStoreObject> {
            let range = (Swift.max(0, minCount) ... maxCount)
            self.minCount = range.lowerBound
            self.maxCount = range.upperBound
+            self.affectedByKeyPaths = affectedByKeyPaths
        }
    }
    
@@ -466,10 +612,27 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, deleteRule: DeleteRule = .nullify, minCount: Int = 0, maxCount: Int = 0, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            deleteRule: DeleteRule = .nullify,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { nil }, deleteRule: deleteRule, minCount: minCount, maxCount: maxCount, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { nil },
+                deleteRule: deleteRule,
+                minCount: minCount,
+                maxCount: maxCount,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -489,10 +652,28 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, inverse: @escaping (D) -> RelationshipContainer<D>.ToOne<O>, deleteRule: DeleteRule = .nullify, minCount: Int = 0, maxCount: Int = 0, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToOne<O>,
+            deleteRule: DeleteRule = .nullify,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, minCount: minCount, maxCount: maxCount, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                minCount: minCount,
+                maxCount: maxCount,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -512,10 +693,28 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, inverse: @escaping (D) -> RelationshipContainer<D>.ToManyOrdered<O>, deleteRule: DeleteRule = .nullify, minCount: Int = 0, maxCount: Int = 0, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToManyOrdered<O>,
+            deleteRule: DeleteRule = .nullify,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, minCount: minCount, maxCount: maxCount, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                minCount: minCount,
+                maxCount: maxCount,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -535,10 +734,28 @@ public enum RelationshipContainer<O: CoreStoreObject> {
         - parameter deleteRule: defines what happens to relationship when an object is deleted. Valid values are `.nullify`, `.cascade`, and `.delete`. Defaults to `.nullify`.
         - parameter versionHashModifier: used to mark or denote a relationship as being a different "version" than another even if all of the values which affect persistence are equal. (Such a difference is important in cases where the properties are unchanged but the format or content of its data are changed.)
         - parameter renamingIdentifier: used to resolve naming conflicts between models. When creating an entity mapping between entities in two managed object models, a source entity property and a destination entity property that share the same identifier indicate that a property mapping should be configured to migrate from the source to the destination. If unset, the identifier will be the property's name.
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public convenience init(_ keyPath: KeyPath, inverse: @escaping (D) -> RelationshipContainer<D>.ToManyUnordered<O>, deleteRule: DeleteRule = .nullify, minCount: Int = 0, maxCount: Int = 0, versionHashModifier: String? = nil, renamingIdentifier: String? = nil) {
+        public convenience init(
+            _ keyPath: KeyPath,
+            inverse: @escaping (D) -> RelationshipContainer<D>.ToManyUnordered<O>,
+            deleteRule: DeleteRule = .nullify,
+            minCount: Int = 0,
+            maxCount: Int = 0,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
-            self.init(keyPath: keyPath, inverseKeyPath: { inverse(D.meta).keyPath }, deleteRule: deleteRule, minCount: minCount, maxCount: maxCount, versionHashModifier: versionHashModifier, renamingIdentifier: renamingIdentifier)
+            self.init(
+                keyPath: keyPath,
+                inverseKeyPath: { inverse(D.meta).keyPath },
+                deleteRule: deleteRule,
+                minCount: minCount,
+                maxCount: maxCount,
+                versionHashModifier: versionHashModifier,
+                renamingIdentifier: renamingIdentifier,
+                affectedByKeyPaths: affectedByKeyPaths
+            )
        }
        
        /**
@@ -570,48 +787,57 @@ public enum RelationshipContainer<O: CoreStoreObject> {
        internal let inverse: (type: CoreStoreObject.Type, keyPath: () -> KeyPath?)
        internal let versionHashModifier: String?
        internal let renamingIdentifier: String?
-        
-        internal var parentObject: () -> CoreStoreObject = {
-            
-            CoreStore.abort("Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types.")
-        }
+        internal let affectedByKeyPaths: () -> Set<String>
+        internal weak var parentObject: CoreStoreObject?
        
        internal var nativeValue: NSSet {
            
            get {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                return object.rawObject!.getValue(
-                    forKvcKey: self.keyPath,
-                    didGetValue: { ($0 as! NSSet?) ?? [] }
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    return object.rawObject!.getValue(
+                        forKvcKey: self.keyPath,
+                        didGetValue: { ($0 as! NSSet?) ?? [] }
+                    )
+                }
            }
            set {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                CoreStore.assert(
-                    object.rawObject!.isEditableInContext() == true,
-                    "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
-                )
-                object.rawObject!.setValue(
-                    newValue,
-                    forKvcKey: self.keyPath
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    )
+                    object.rawObject!.setValue(
+                        newValue,
+                        forKvcKey: self.keyPath
+                    )
+                }
            }
        }
        
        
        // MARK: Private
        
-        private init(keyPath: KeyPath, inverseKeyPath: @escaping () -> KeyPath?, deleteRule: DeleteRule, minCount: Int, maxCount: Int, versionHashModifier: String?, renamingIdentifier: String?) {
+        private init(keyPath: KeyPath, inverseKeyPath: @escaping () -> KeyPath?, deleteRule: DeleteRule, minCount: Int, maxCount: Int, versionHashModifier: String?, renamingIdentifier: String?, affectedByKeyPaths: @autoclosure @escaping () -> Set<String>) {
            
            self.keyPath = keyPath
            self.deleteRule = deleteRule.nativeValue
@@ -622,6 +848,7 @@ public enum RelationshipContainer<O: CoreStoreObject> {
            let range = (Swift.max(0, minCount) ... maxCount)
            self.minCount = range.lowerBound
            self.maxCount = range.upperBound
+            self.affectedByKeyPaths = affectedByKeyPaths
        }
    }
    
@@ -658,7 +885,7 @@ extension RelationshipContainer.ToManyOrdered: RandomAccessCollection {
    public func makeIterator() -> Iterator {
        
        let iterator = self.nativeValue.makeIterator()
-        return AnyIterator({ D.cs_fromRaw(object: iterator.next() as! NSManagedObject) })
+        return AnyIterator({ iterator.next().flatMap({ D.cs_fromRaw(object: $0 as! NSManagedObject) }) })
    }
    
    
@@ -713,7 +940,7 @@ extension RelationshipContainer.ToManyUnordered: Sequence {
    public func makeIterator() -> Iterator {
        
        let iterator = self.nativeValue.makeIterator()
-        return AnyIterator({ D.cs_fromRaw(object: iterator.next() as! NSManagedObject) })
+        return AnyIterator({ iterator.next().flatMap({ D.cs_fromRaw(object: $0 as! NSManagedObject) }) })
    }
 }

@@ -988,7 +1215,8 @@ internal protocol RelationshipProtocol: class {
    var isOrdered: Bool { get }
    var deleteRule: NSDeleteRule { get }
    var inverse: (type: CoreStoreObject.Type, keyPath: () -> KeyPath?) { get }
-    var parentObject: () -> CoreStoreObject { get set }
+    var affectedByKeyPaths: () -> Set<String> { get }
+    weak var parentObject: CoreStoreObject? { get set }
    var versionHashModifier: String? { get }
    var renamingIdentifier: String? { get }
    var minCount: Int { get }
--- a/Sources/Value.swift
+++ b/Sources/Value.swift
@@ -114,17 +114,28 @@ public enum ValueContainer<O: CoreStoreObject> {
         - parameter setValue: the original setter for the property
         - parameter finalNewValue: the transformed new value
         - parameter originalNewValue: the original new value
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public init(_ keyPath: KeyPath, `default`: V, isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V) -> V = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void = { $1($2) }) {
+        public init(
+            _ keyPath: KeyPath,
+            `default`: @autoclosure @escaping () -> V,
+            isIndexed: Bool = false,
+            isTransient: Bool = false,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)? = nil,
+            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void)? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
            self.keyPath = keyPath
            self.isIndexed = isIndexed
            self.isTransient = isTransient
-            self.defaultValue = `default`.cs_toImportableNativeType()
+            self.defaultValue = { `default`().cs_toImportableNativeType() }
            self.versionHashModifier = versionHashModifier
            self.renamingIdentifier = renamingIdentifier
            self.customGetter = customGetter
            self.customSetter = customSetter
+            self.affectedByKeyPaths = affectedByKeyPaths
        }
        
        /**
@@ -134,45 +145,103 @@ public enum ValueContainer<O: CoreStoreObject> {
            
            get {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                return self.customGetter(
-                    object,
-                    { () -> V in
-                        
-                        return object.rawObject!.getValue(
-                            forKvcKey: self.keyPath,
-                            didGetValue: { V.cs_fromImportableNativeType($0 as! V.ImportableNativeType)! }
-                        )
-                    }
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    let customGetter = (self.customGetter ?? { $1() })
+                    return customGetter(
+                        object,
+                        { () -> V in
+                            
+                            return V.cs_fromImportableNativeType(
+                                object.rawObject!.value(forKey: self.keyPath)! as! V.ImportableNativeType
+                            )!
+                        }
+                    )
+                }
            }
            set {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    )
+                    let customSetter = (self.customSetter ?? { $1($2) })
+                    customSetter(
+                        object,
+                        { (newValue: V) -> Void in
+                            
+                            object.rawObject!.setValue(
+                                newValue.cs_toImportableNativeType(),
+                                forKey: self.keyPath
+                            )
+                        },
+                        newValue
+                    )
+                }
+            }
+        }
+        
+        /**
+         The primitive value. Compared to `value`, `primitiveValue` bypasses all notification mechanisms. This is typically only used for setting values for transient properties.
+         */
+        public var primitiveValue: V {
+            
+            get {
+                
                CoreStore.assert(
-                    object.rawObject!.isEditableInContext() == true,
-                    "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
-                self.customSetter(
-                    object,
-                    { (newValue: V) -> Void in
-                        
-                        object.rawObject!.setValue(
-                            newValue,
-                            forKvcKey: self.keyPath,
-                            willSetValue: { $0.cs_toImportableNativeType() }
-                        )
-                    },
-                    newValue
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    return V.cs_fromImportableNativeType(
+                        object.rawObject!.primitiveValue(forKey: self.keyPath)! as! V.ImportableNativeType
+                    )!
+                }
+            }
+            set {
+                
+                CoreStore.assert(
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s primitive value from outside a transaction."
+                    )
+                    object.rawObject!.setPrimitiveValue(
+                        newValue.cs_toImportableNativeType(),
+                        forKey: self.keyPath
+                    )
+                }
            }
        }
        
@@ -189,20 +258,65 @@ public enum ValueContainer<O: CoreStoreObject> {
        internal let isOptional = false
        internal let isIndexed: Bool
        internal let isTransient: Bool
-        internal let defaultValue: Any?
        internal let versionHashModifier: String?
        internal let renamingIdentifier: String?
+        internal let defaultValue: () -> Any?
+        internal let affectedByKeyPaths: () -> Set<String>
+        internal weak var parentObject: CoreStoreObject?
        
-        internal var parentObject: () -> CoreStoreObject = {
+        internal private(set) lazy var getter: CoreStoreManagedObject.CustomGetter? = cs_lazy { [unowned self] in
            
-            CoreStore.abort("Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types.")
+            guard let customGetter = self.customGetter else {
+                
+                return nil
+            }
+            let keyPath = self.keyPath
+            return { (_ id: Any) -> Any? in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                let value = customGetter(
+                    O.cs_fromRaw(object: rawObject),
+                    {
+                        rawObject.getValue(
+                            forKvcKey: keyPath,
+                            didGetValue: { V.cs_fromImportableNativeType($0 as! V.ImportableNativeType!)! }
+                        )
+                    }
+                )
+                return value.cs_toImportableNativeType()
+            }
+        }
+        
+        internal private(set) lazy var setter: CoreStoreManagedObject.CustomSetter? = cs_lazy { [unowned self] in
+            
+            guard let customSetter = self.customSetter else {
+                
+                return nil
+            }
+            let keyPath = self.keyPath
+            return { (_ id: Any, _ newValue: Any?) -> Void in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                customSetter(
+                    O.cs_fromRaw(object: rawObject),
+                    { (userValue: V) -> Void in
+                        
+                        rawObject.setValue(
+                            userValue,
+                            forKvcKey: keyPath,
+                            willSetValue: { $0.cs_toImportableNativeType() }
+                        )
+                    },
+                    V.cs_fromImportableNativeType(newValue as! V.ImportableNativeType)!
+                )
+            }
        }
        
        
        // MARK: Private
        
-        private let customGetter: (_ `self`: O, _ getValue: () -> V) -> V
-        private let customSetter: (_ `self`: O, _ setValue: (V) -> Void, _ newValue: V) -> Void
+        private let customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)?
+        private let customSetter: ((_ `self`: O, _ setValue: (V) -> Void, _ newValue: V) -> Void)?
    }
    
    
@@ -247,17 +361,28 @@ public enum ValueContainer<O: CoreStoreObject> {
         - parameter setValue: the original setter for the property
         - parameter finalNewValue: the transformed new value
         - parameter originalNewValue: the original new value
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public init(_ keyPath: KeyPath, `default`: V? = nil, isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V?) -> V? = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V?) -> Void, _ originalNewValue: V?) -> Void = { $1($2) }) {
+        public init(
+            _ keyPath: KeyPath,
+            `default`: @autoclosure @escaping () -> V? = nil,
+            isIndexed: Bool = false,
+            isTransient: Bool = false,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)? = nil,
+            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V?) -> Void, _ originalNewValue: V?) -> Void)? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
            self.keyPath = keyPath
            self.isIndexed = isIndexed
            self.isTransient = isTransient
-            self.defaultValue = `default`?.cs_toImportableNativeType()
+            self.defaultValue = { `default`()?.cs_toImportableNativeType() }
            self.versionHashModifier = versionHashModifier
            self.renamingIdentifier = renamingIdentifier
            self.customGetter = customGetter
            self.customSetter = customSetter
+            self.affectedByKeyPaths = affectedByKeyPaths
        }
        
        /**
@@ -267,45 +392,101 @@ public enum ValueContainer<O: CoreStoreObject> {
            
            get {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                return self.customGetter(
-                    object,
-                    { () -> V? in
-                        
-                        return object.rawObject!.getValue(
-                            forKvcKey: self.keyPath,
-                            didGetValue: { ($0 as! V.ImportableNativeType?).flatMap(V.cs_fromImportableNativeType) }
-                        )
-                    }
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    let customGetter = (self.customGetter ?? { $1() })
+                    return customGetter(
+                        object,
+                        { () -> V? in
+                            
+                            return (object.rawObject!.value(forKey: self.keyPath) as! V.ImportableNativeType?)
+                                .flatMap(V.cs_fromImportableNativeType)
+                        }
+                    )
+                }
            }
            set {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    )
+                    let customSetter = (self.customSetter ?? { $1($2) })
+                    customSetter(
+                        object,
+                        { (newValue: V?) -> Void in
+                            
+                            object.rawObject!.setValue(
+                                newValue?.cs_toImportableNativeType(),
+                                forKey: self.keyPath
+                            )
+                        },
+                        newValue
+                    )
+                }
+            }
+        }
+        
+        /**
+         The primitive value. Compared to `value`, `primitiveValue` bypasses all notification mechanisms. This is typically only used for setting values for transient properties.
+         */
+        public var primitiveValue: V? {
+            
+            get {
+                
                CoreStore.assert(
-                    object.rawObject!.isEditableInContext() == true,
-                    "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
-                self.customSetter(
-                    object,
-                    { (newValue: V?) -> Void in
-                        
-                        object.rawObject!.setValue(
-                            newValue,
-                            forKvcKey: self.keyPath,
-                            willSetValue: { $0?.cs_toImportableNativeType() }
-                        )
-                    },
-                    newValue
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    return (object.rawObject!.primitiveValue(forKey: self.keyPath) as! V.ImportableNativeType?)
+                        .flatMap(V.cs_fromImportableNativeType)
+                }
+            }
+            set {
+                
+                CoreStore.assert(
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s primitive value from outside a transaction."
+                    )
+                    object.rawObject!.setPrimitiveValue(
+                        newValue?.cs_toImportableNativeType(),
+                        forKey: self.keyPath
+                    )
+                }
            }
        }
        
@@ -321,20 +502,65 @@ public enum ValueContainer<O: CoreStoreObject> {
        internal let isOptional = true
        internal let isIndexed: Bool
        internal let isTransient: Bool
-        internal let defaultValue: Any?
        internal let versionHashModifier: String?
        internal let renamingIdentifier: String?
+        internal let defaultValue: () -> Any?
+        internal let affectedByKeyPaths: () -> Set<String>
+        internal weak var parentObject: CoreStoreObject?
        
-        internal var parentObject: () -> CoreStoreObject = {
+        internal private(set) lazy var getter: CoreStoreManagedObject.CustomGetter? = cs_lazy { [unowned self] in
            
-            CoreStore.abort("Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types.")
+            guard let customGetter = self.customGetter else {
+                
+                return nil
+            }
+            let keyPath = self.keyPath
+            return { (_ id: Any) -> Any? in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                let value = customGetter(
+                    O.cs_fromRaw(object: rawObject),
+                    {
+                        rawObject.getValue(
+                            forKvcKey: keyPath,
+                            didGetValue: { ($0 as! V.ImportableNativeType?).flatMap(V.cs_fromImportableNativeType) }
+                        )
+                    }
+                )
+                return value?.cs_toImportableNativeType()
+            }
+        }
+        
+        internal private(set) lazy var setter: CoreStoreManagedObject.CustomSetter? = cs_lazy { [unowned self] in
+            
+            guard let customSetter = self.customSetter else {
+                
+                return nil
+            }
+            let keyPath = self.keyPath
+            return { (_ id: Any, _ newValue: Any?) -> Void in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                customSetter(
+                    O.cs_fromRaw(object: rawObject),
+                    { (userValue: V?) -> Void in
+                        
+                        rawObject.setValue(
+                            userValue,
+                            forKvcKey: keyPath,
+                            willSetValue: { $0?.cs_toImportableNativeType() }
+                        )
+                    },
+                    (newValue as! V.ImportableNativeType?).flatMap(V.cs_fromImportableNativeType)
+                )
+            }
        }
        
        
        // MARK: Private
        
-        private let customGetter: (_ `self`: O, _ getValue: () -> V?) -> V?
-        private let customSetter: (_ `self`: O, _ setValue: (V?) -> Void, _ newValue: V?) -> Void
+        private let customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)?
+        private let customSetter: ((_ `self`: O, _ setValue: (V?) -> Void, _ newValue: V?) -> Void)?
    }
 }

@@ -359,8 +585,17 @@ public extension ValueContainer.Required where V: EmptyableAttributeType {
     - parameter setValue: the original setter for the property
     - parameter finalNewValue: the transformed new value
     - parameter originalNewValue: the original new value
+     - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
     */
-    public convenience init(_ keyPath: KeyPath, isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V) -> V = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void = { $1($2) }) {
+    public convenience init(
+        _ keyPath: KeyPath,
+        isIndexed: Bool = false,
+        isTransient: Bool = false,
+        versionHashModifier: String? = nil,
+        renamingIdentifier: String? = nil,
+        customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)? = nil,
+        customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void)? = nil,
+        affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
        
        self.init(
            keyPath,
@@ -370,7 +605,8 @@ public extension ValueContainer.Required where V: EmptyableAttributeType {
            versionHashModifier: versionHashModifier,
            renamingIdentifier: renamingIdentifier,
            customGetter: customGetter,
-            customSetter: customSetter
+            customSetter: customSetter,
+            affectedByKeyPaths: affectedByKeyPaths
        )
    }
 }
@@ -425,8 +661,18 @@ public enum TransformableContainer<O: CoreStoreObject> {
         - parameter setValue: the original setter for the property
         - parameter finalNewValue: the transformed new value
         - parameter originalNewValue: the original new value
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public init(_ keyPath: KeyPath, `default`: V, isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V) -> V = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void = { $1($2) }) {
+        public init(
+            _ keyPath: KeyPath,
+            `default`: @autoclosure @escaping () -> V,
+            isIndexed: Bool = false,
+            isTransient: Bool = false,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)? = nil,
+            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V) -> Void, _ originalNewValue: V) -> Void)? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
            self.keyPath = keyPath
            self.defaultValue = `default`
@@ -436,6 +682,7 @@ public enum TransformableContainer<O: CoreStoreObject> {
            self.renamingIdentifier = renamingIdentifier
            self.customGetter = customGetter
            self.customSetter = customSetter
+            self.affectedByKeyPaths = affectedByKeyPaths
        }
        
        /**
@@ -445,44 +692,99 @@ public enum TransformableContainer<O: CoreStoreObject> {
            
            get {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                return self.customGetter(
-                    object,
-                    { () -> V in
-                        
-                        return object.rawObject!.getValue(
-                            forKvcKey: self.keyPath,
-                            didGetValue: { $0 as! V }
-                        )
-                    }
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    let customGetter = (self.customGetter ?? { $1() })
+                    return customGetter(
+                        object,
+                        { () -> V in
+                            
+                            return object.rawObject!.value(forKey: self.keyPath)! as! V
+                        }
+                    )
+                }
            }
            set {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    )
+                    let customSetter = (self.customSetter ?? { $1($2) })
+                    customSetter(
+                        object,
+                        { (newValue: V) -> Void in
+                            
+                            object.rawObject!.setValue(
+                                newValue,
+                                forKey: self.keyPath
+                            )
+                        },
+                        newValue
+                    )
+                }
+            }
+        }
+        
+        /**
+         The primitive value. Compared to `value`, `primitiveValue` bypasses all notification mechanisms. This is typically only used for setting values for transient properties.
+         */
+        public var primitiveValue: V {
+            
+            get {
+                
                CoreStore.assert(
-                    object.rawObject!.isEditableInContext() == true,
-                    "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
-                self.customSetter(
-                    object,
-                    { (newValue: V) -> Void in
-                        
-                        object.rawObject!.setValue(
-                            newValue,
-                            forKvcKey: self.keyPath
-                        )
-                    },
-                    newValue
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    return object.rawObject!.primitiveValue(forKey: self.keyPath)! as! V
+                }
+            }
+            set {
+                
+                CoreStore.assert(
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s primitive value from outside a transaction."
+                    )
+                    object.rawObject!.setPrimitiveValue(
+                        newValue,
+                        forKey: self.keyPath
+                    )
+                }
            }
        }
        
@@ -499,20 +801,55 @@ public enum TransformableContainer<O: CoreStoreObject> {
        internal let isOptional = false
        internal let isIndexed: Bool
        internal let isTransient: Bool
-        internal let defaultValue: Any?
        internal let versionHashModifier: String?
        internal let renamingIdentifier: String?
+        internal let defaultValue: () -> Any?
+        internal let affectedByKeyPaths: () -> Set<String>
+        internal weak var parentObject: CoreStoreObject?
        
-        internal var parentObject: () -> CoreStoreObject = {
+        internal private(set) lazy var getter: CoreStoreManagedObject.CustomGetter? = cs_lazy { [unowned self] in
            
-            CoreStore.abort("Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types.")
+            guard let customGetter = self.customGetter else {
+                
+                return nil
+            }
+            let keyPath = self.keyPath
+            return { (_ id: Any) -> Any? in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                return customGetter(
+                    O.cs_fromRaw(object: rawObject),
+                    { rawObject.getValue(forKvcKey: keyPath) as! V }
+                )
+            }
+        }
+        
+        internal private(set) lazy var setter: CoreStoreManagedObject.CustomSetter? = cs_lazy { [unowned self] in
+            
+            guard let customSetter = self.customSetter else {
+                
+                return nil
+            }
+            let keyPath = self.keyPath
+            return { (_ id: Any, _ newValue: Any?) -> Void in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                customSetter(
+                    O.cs_fromRaw(object: rawObject),
+                    { (userValue: V) -> Void in
+                        
+                        rawObject.setValue(userValue, forKvcKey: keyPath)
+                    },
+                    newValue as! V
+                )
+            }
        }
        
        
        // MARK: Private
        
-        private let customGetter: (_ `self`: O, _ getValue: () -> V) -> V
-        private let customSetter: (_ `self`: O, _ setValue: (V) -> Void, _ newValue: V) -> Void
+        private let customGetter: ((_ `self`: O, _ getValue: () -> V) -> V)?
+        private let customSetter: ((_ `self`: O, _ setValue: (V) -> Void, _ newValue: V) -> Void)?
    }
    
    
@@ -551,8 +888,18 @@ public enum TransformableContainer<O: CoreStoreObject> {
         - parameter setValue: the original setter for the property
         - parameter finalNewValue: the transformed new value
         - parameter originalNewValue: the original new value
+         - parameter affectedByKeyPaths: a set of key paths for properties whose values affect the value of the receiver. This is similar to `NSManagedObject.keyPathsForValuesAffectingValue(forKey:)`.
         */
-        public init(_ keyPath: KeyPath, `default`: V? = nil, isIndexed: Bool = false, isTransient: Bool = false, versionHashModifier: String? = nil, renamingIdentifier: String? = nil, customGetter: @escaping (_ `self`: O, _ getValue: () -> V?) -> V? = { $1() }, customSetter: @escaping (_ `self`: O, _ setValue: (_ finalNewValue: V?) -> Void, _ originalNewValue: V?) -> Void = { $1($2) }) {
+        public init(
+            _ keyPath: KeyPath,
+            `default`: @autoclosure @escaping () -> V? = nil,
+            isIndexed: Bool = false,
+            isTransient: Bool = false,
+            versionHashModifier: String? = nil,
+            renamingIdentifier: String? = nil,
+            customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)? = nil,
+            customSetter: ((_ `self`: O, _ setValue: (_ finalNewValue: V?) -> Void, _ originalNewValue: V?) -> Void)? = nil,
+            affectedByKeyPaths: @autoclosure @escaping () -> Set<String> = []) {
            
            self.keyPath = keyPath
            self.defaultValue = `default`
@@ -562,6 +909,7 @@ public enum TransformableContainer<O: CoreStoreObject> {
            self.renamingIdentifier = renamingIdentifier
            self.customGetter = customGetter
            self.customSetter = customSetter
+            self.affectedByKeyPaths = affectedByKeyPaths
        }
        
        /**
@@ -571,44 +919,99 @@ public enum TransformableContainer<O: CoreStoreObject> {
            
            get {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
-                )
-                return self.customGetter(
-                    object,
-                    { () -> V? in
-                        
-                        return object.rawObject!.getValue(
-                            forKvcKey: self.keyPath,
-                            didGetValue: { $0 as! V? }
-                        )
-                    }
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    let customGetter = (self.customGetter ?? { $1() })
+                    return customGetter(
+                        object,
+                        { () -> V? in
+                            
+                            object.rawObject!.value(forKey: self.keyPath) as! V?
+                        }
+                    )
+                }
            }
            set {
                
-                let object = self.parentObject() as! O
                CoreStore.assert(
-                    object.rawObject!.isRunningInAllowedQueue() == true,
-                    "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    self.parentObject != nil,
+                    "Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    )
+                    let customSetter = (self.customSetter ?? { $1($2) })
+                    customSetter(
+                        object,
+                        { (newValue: V?) -> Void in
+                            
+                            object.rawObject!.setValue(
+                                newValue,
+                                forKey: self.keyPath
+                            )
+                        },
+                        newValue
+                    )
+                }
+            }
+        }
+        
+        /**
+         The primitive value. Compared to `value`, `primitiveValue` bypasses all notification mechanisms. This is typically only used for setting values for transient properties.
+         */
+        public var primitiveValue: V? {
+            
+            get {
+                
                CoreStore.assert(
-                    object.rawObject!.isEditableInContext() == true,
-                    "Attempted to update a \(cs_typeName(O.self))'s value from outside a transaction."
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
-                self.customSetter(
-                    object,
-                    { (newValue: V?) -> Void in
-                        
-                        object.rawObject!.setValue(
-                            newValue,
-                            forKvcKey: self.keyPath
-                        )
-                    },
-                    newValue
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    return object.rawObject!.primitiveValue(forKey: self.keyPath) as! V?
+                }
+            }
+            set {
+                
+                CoreStore.assert(
+                    self.parentObject != nil,
+                    "Attempted to access primitive values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types."
                )
+                return withExtendedLifetime(self.parentObject! as! O) { (object: O) in
+                    
+                    CoreStore.assert(
+                        object.rawObject!.isRunningInAllowedQueue() == true,
+                        "Attempted to access \(cs_typeName(O.self))'s primitive value outside it's designated queue."
+                    )
+                    CoreStore.assert(
+                        self.isTransient || object.rawObject!.isEditableInContext() == true,
+                        "Attempted to update a \(cs_typeName(O.self))'s primitive value from outside a transaction."
+                    )
+                    object.rawObject!.setPrimitiveValue(
+                        newValue,
+                        forKey: self.keyPath
+                    )
+                }
            }
        }
        
@@ -625,20 +1028,63 @@ public enum TransformableContainer<O: CoreStoreObject> {
        internal let isOptional = true
        internal let isIndexed: Bool
        internal let isTransient: Bool
-        internal let defaultValue: Any?
        internal let versionHashModifier: String?
        internal let renamingIdentifier: String?
+        internal let defaultValue: () -> Any?
+        internal let affectedByKeyPaths: () -> Set<String>
+        internal weak var parentObject: CoreStoreObject?
        
-        internal var parentObject: () -> CoreStoreObject = {
+        internal private(set) lazy var getter: CoreStoreManagedObject.CustomGetter? = cs_lazy { [unowned self] in
            
-            CoreStore.abort("Attempted to access values from a \(cs_typeName(O.self)) meta object. Meta objects are only used for querying keyPaths and infering types.")
+            guard let customGetter = self.customGetter else {
+                
+                return nil
+            }
+            let keyPath = self.keyPath
+            return { (_ id: Any) -> Any? in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                return customGetter(
+                    O.cs_fromRaw(object: rawObject),
+                    { rawObject.getValue(forKvcKey: keyPath) as! V? }
+                )
+            }
+        }
+        
+        internal private(set) lazy var setter: CoreStoreManagedObject.CustomSetter? = cs_lazy { [unowned self] in
+            
+            let keyPath = self.keyPath
+            guard let customSetter = self.customSetter else {
+                
+                guard let _ = self.customGetter else {
+                    
+                    return nil
+                }
+                return { (_ id: Any, _ newValue: Any?) -> Void in
+                    
+                    let rawObject = id as! CoreStoreManagedObject
+                    rawObject.setValue(newValue, forKvcKey: keyPath)
+                }
+            }
+            return { (_ id: Any, _ newValue: Any?) -> Void in
+                
+                let rawObject = id as! CoreStoreManagedObject
+                customSetter(
+                    O.cs_fromRaw(object: rawObject),
+                    { (userValue: V?) -> Void in
+                        
+                        rawObject.setValue(userValue, forKvcKey: keyPath)
+                    },
+                    newValue as! V?
+                )
+            }
        }
        
        
        // MARK: Private
        
-        private let customGetter: (_ `self`: O, _ getValue: () -> V?) -> V?
-        private let customSetter: (_ `self`: O, _ setValue: (V?) -> Void, _ newValue: V?) -> Void
+        private let customGetter: ((_ `self`: O, _ getValue: () -> V?) -> V?)?
+        private let customSetter: ((_ `self`: O, _ setValue: (V?) -> Void, _ newValue: V?) -> Void)?
    }
 }

@@ -941,8 +1387,11 @@ internal protocol AttributeProtocol: class {
    var isOptional: Bool { get }
    var isIndexed: Bool { get }
    var isTransient: Bool { get }
-    var defaultValue: Any? { get }
    var versionHashModifier: String? { get }
    var renamingIdentifier: String? { get }
-    var parentObject: () -> CoreStoreObject { get set }
+    var defaultValue: () -> Any? { get }
+    var affectedByKeyPaths: () -> Set<String> { get }
+    weak var parentObject: CoreStoreObject? { get set }
+    var getter: CoreStoreManagedObject.CustomGetter? { get }
+    var setter: CoreStoreManagedObject.CustomSetter? { get }
 }
--- a/Sources/XcodeSchemaMappingProvider.swift
+++ b/Sources/XcodeSchemaMappingProvider.swift
@@ -32,7 +32,7 @@ import Foundation
 /**
 A `SchemaMappingProvider` that tries to infer model migration between two `DynamicSchema` versions by loading an xcmappingmodel file from the specified `Bundle`. Throws `CoreStoreError.mappingModelNotFound` if the xcmappingmodel file cannot be found, or if the xcmappingmodel doesn't resolve the source and destination `DynamicSchema`.
 */
-final class XcodeSchemaMappingProvider: Hashable, SchemaMappingProvider {
+public final class XcodeSchemaMappingProvider: Hashable, SchemaMappingProvider {
    
    /**
     The source model version for the mapping.
Author	SHA1	Message	Date
John Estropia	5689158b43	version bump	2017-06-14 21:50:58 +09:00
John Estropia	6fcdf3d011	fix logger demo	2017-06-14 17:43:34 +09:00
John Estropia	e26573c18e	converted the Demo app's observer demo to use CoreStoreObject instead of NSManagedObject	2017-06-14 17:39:57 +09:00
John Estropia	801cf8d9f0	Fixed ListMonitor bug for CoreStoreObjects where ListObservers don't get update notifications	2017-06-14 17:37:46 +09:00
John Rommel Estropia	8c437e19b8	version bump	2017-06-10 23:19:02 +09:00
John Rommel Estropia	9cd3b6c879	code cleanup	2017-06-10 22:13:32 +09:00
John Rommel Estropia	fe135acbec	Improve CoreStoreObjects KVO behavior	2017-06-10 21:02:36 +09:00
John Estropia	997c5bdcfa	uniquify subclass names across model versions	2017-06-09 12:47:22 +09:00
John Rommel Estropia	129f975d96	version bump	2017-06-08 01:17:39 +09:00
John Rommel Estropia	a2e463e58c	Merge branch 'prototype/customMigrationTest' of github.com:JohnEstropia/CoreStore into prototype/customMigrationTest	2017-06-08 01:07:00 +09:00
John Rommel Estropia	5fd50f0e15	fix migration for CoreStoreObject relationships	2017-06-08 01:06:51 +09:00
John Estropia	0a81736b7a	Merge branch 'develop' into prototype/customMigrationTest	2017-06-07 12:31:42 +09:00
John Estropia	f9b6dd0c6a	fix bug when using ObjectMonitor with CoreStoreObjects	2017-06-06 17:40:29 +09:00
John Rommel Estropia	0354401b56	WIP: bugfix for CustomSchemaMappingProvider relationship migration bug	2017-06-06 08:39:59 +09:00
John Rommel Estropia	0304067beb	fix ToManyOrdered and ToManyUnordered enumeration crash	2017-06-06 00:49:16 +09:00
John Rommel Estropia	ddd83da434	add Where comparison operators for optional values	2017-06-05 23:09:19 +09:00
John Estropia	fc7df671de	Fixes https://bugs.swift.org/browse/SR-4981	2017-06-05 12:45:35 +09:00
John Rommel Estropia	5fde9030c7	use stronger namespace for CoreStoreObject's internal managed object type	2017-06-05 08:03:37 +09:00
John Rommel Estropia	d7b07b3f00	Added alternative way to set keyPathsForValuesAffectingValue(forKey:) for CoreStoreObjects	2017-06-05 01:30:26 +09:00
John Rommel Estropia	ddd1ffb29f	added ~= operation to create Where clauses for value arrays	2017-06-03 08:51:52 +09:00
John Rommel Estropia	98094000bb	Merge branch 'master' into develop	2017-06-02 23:10:31 +09:00
John Estropia	d5026ef996	Merge branch 'temp/develop' into develop	2017-06-02 19:35:01 +09:00
John Estropia	2cd913b9dd	added more utilities for CoreStoreObject meta	2017-06-02 19:34:54 +09:00
John Estropia	ad9520abbc	Update README.md	2017-06-02 13:24:15 +09:00
John Estropia	c0fc57d10c	Update README.md	2017-06-02 11:34:04 +09:00
John Estropia	0cf4d303e4	Added README sample on how to version CoreStoreObjects	2017-06-02 11:32:48 +09:00
John Rommel Estropia	6de397958a	fix demo app warnings	2017-06-02 02:06:47 +09:00
John Rommel Estropia	55292a84dc	made mapping modell providers public	2017-06-02 02:03:41 +09:00