Add docs for new throwing methods

CoreStoreTests/DynamicModelTests.swift

@@ -266,6 +266,9 @@ class DynamicModelTests: BaseTestDataTestCase {
                     
                     let p3 = Where<Dog>({ $0.age == 10 })
                     XCTAssertEqual(p3.predicate, NSPredicate(format: "%K == %d", "age", 10))
+
+                    let totalAge = try transaction.queryValue(From<Dog>().select(Int.self, .sum(\Dog.age)))
+                    XCTAssertEqual(totalAge, 1)
                     
                     _ = try transaction.fetchAll(
                         From<Dog>()

Sources/BaseDataTransaction+Querying.swift

@@ -136,7 +136,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D? {
         
@@ -152,7 +153,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D? {
         
@@ -173,7 +175,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
         
@@ -189,7 +192,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D] {
         
@@ -205,7 +209,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D] {
         
@@ -226,7 +231,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
         
@@ -242,7 +248,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int {
         
@@ -258,7 +265,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int {
         
@@ -279,7 +287,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
@@ -295,7 +304,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
         
@@ -311,7 +321,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
         
@@ -332,7 +343,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
         
@@ -348,7 +360,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
         
@@ -364,7 +377,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
         
@@ -385,7 +399,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
         
@@ -407,7 +422,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U? {
         
@@ -426,7 +442,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U? {
         
@@ -449,7 +466,8 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
-     - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - returns: the result of the the query as specified by the `QueryChainableBuilderType`, or `nil` if no match was found.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType {
         
@@ -469,6 +487,7 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
         
@@ -488,6 +507,7 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
         
@@ -520,6 +540,7 @@ extension BaseDataTransaction: FetchableSource, QueryableSource {
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary {
         

Sources/CoreStore+Querying.swift

@@ -80,7 +80,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D? {
         
@@ -92,7 +93,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D? {
         
@@ -109,7 +111,8 @@ public extension CoreStore {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
         
@@ -121,7 +124,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D] {
         
@@ -133,7 +137,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D] {
         
@@ -150,7 +155,8 @@ public extension CoreStore {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
         
@@ -162,7 +168,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int {
         
@@ -174,7 +181,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int {
         
@@ -191,7 +199,8 @@ public extension CoreStore {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
@@ -203,7 +212,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
         
@@ -215,7 +225,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
         
@@ -232,7 +243,8 @@ public extension CoreStore {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
         
@@ -244,7 +256,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
         
@@ -256,7 +269,8 @@ public extension CoreStore {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
         
@@ -273,7 +287,8 @@ public extension CoreStore {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
         
@@ -288,7 +303,8 @@ public extension CoreStore {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U? {
         
@@ -303,7 +319,8 @@ public extension CoreStore {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U? {
         
@@ -322,7 +339,8 @@ public extension CoreStore {
      )
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
-     - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - returns: the result of the the query as specified by the `QueryChainableBuilderType`, or `nil` if no match was found.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType {
         
@@ -338,6 +356,7 @@ public extension CoreStore {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
         
@@ -353,6 +372,7 @@ public extension CoreStore {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
         
@@ -381,6 +401,7 @@ public extension CoreStore {
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public static func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary {
         

Sources/DataStack+Querying.swift

@@ -82,7 +82,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D? {
         
@@ -98,7 +99,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D? {
         
@@ -119,7 +121,8 @@ extension DataStack: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType? {
         
@@ -135,7 +138,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D] {
         
@@ -151,7 +155,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D] {
         
@@ -172,7 +177,8 @@ extension DataStack: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType] {
 
@@ -188,7 +194,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int {
         
@@ -204,7 +211,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int {
         
@@ -225,7 +233,8 @@ extension DataStack: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int {
         
@@ -241,7 +250,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID? {
         
@@ -257,7 +267,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID? {
         
@@ -278,7 +289,8 @@ extension DataStack: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID? {
         
@@ -294,7 +306,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID] {
         
@@ -310,7 +323,8 @@ extension DataStack: FetchableSource, QueryableSource {
      
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID] {
         
@@ -331,7 +345,8 @@ extension DataStack: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID] {
         
@@ -353,7 +368,8 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U? {
         
@@ -372,7 +388,8 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U? {
         
@@ -395,7 +412,8 @@ extension DataStack: FetchableSource, QueryableSource {
      )
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
-     - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - returns: the result of the the query as specified by the `QueryChainableBuilderType`, or `nil` if no match was found.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType {
         
@@ -415,6 +433,7 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]] {
         
@@ -434,6 +453,7 @@ extension DataStack: FetchableSource, QueryableSource {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]] {
         
@@ -466,6 +486,7 @@ extension DataStack: FetchableSource, QueryableSource {
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     public func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary {
         

Sources/FetchableSource.swift

@@ -71,7 +71,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchOne<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> D?
 
@@ -80,7 +81,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchOne<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> D?
     
@@ -94,7 +96,8 @@ public protocol FetchableSource: class {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`
+     - returns: the first `DynamicObject` instance that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchOne<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> B.ObjectType?
 
@@ -103,7 +106,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchAll<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [D]
 
@@ -112,7 +116,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchAll<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [D]
     
@@ -126,7 +131,8 @@ public protocol FetchableSource: class {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`
+     - returns: all `DynamicObject` instances that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchAll<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [B.ObjectType]
 
@@ -135,7 +141,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchCount<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> Int
 
@@ -144,7 +151,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchClause`s
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchCount<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> Int
     
@@ -158,7 +166,8 @@ public protocol FetchableSource: class {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the number `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the number of `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchCount<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> Int
 
@@ -167,7 +176,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> NSManagedObjectID?
 
@@ -176,7 +186,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchClause`s, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchObjectID<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> NSManagedObjectID?
     
@@ -190,7 +201,8 @@ public protocol FetchableSource: class {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for the first `DynamicObject` that satisfies the specified `FetchChainableBuilderType`, or `nil` if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchObjectID<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> NSManagedObjectID?
 
@@ -199,7 +211,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: FetchClause...) throws -> [NSManagedObjectID]
 
@@ -208,7 +221,8 @@ public protocol FetchableSource: class {
 
      - parameter from: a `From` clause indicating the entity type
      - parameter fetchClauses: a series of `FetchClause` instances for the fetch request. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchClause`s, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchObjectIDs<D>(_ from: From<D>, _ fetchClauses: [FetchClause]) throws -> [NSManagedObjectID]
     
@@ -222,7 +236,8 @@ public protocol FetchableSource: class {
      )
      ```
      - parameter clauseChain: a `FetchChainableBuilderType` built from a chain of clauses
-     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`
+     - returns: the `NSManagedObjectID` for all `DynamicObject`s that satisfy the specified `FetchChainableBuilderType`, or an empty array if no match was found
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func fetchObjectIDs<B: FetchChainableBuilderType>(_ clauseChain: B) throws -> [NSManagedObjectID]
     

Sources/QueryableSource.swift

@@ -42,7 +42,8 @@ public protocol QueryableSource: class {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: QueryClause...) throws -> U?
 
@@ -54,7 +55,8 @@ public protocol QueryableSource: class {
      - parameter from: a `From` clause indicating the entity type
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
-     - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - returns: the result of the the query, or `nil` if no match was found. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func queryValue<D, U: QueryableAttributeType>(_ from: From<D>, _ selectClause: Select<D, U>, _ queryClauses: [QueryClause]) throws -> U?
     
@@ -70,7 +72,8 @@ public protocol QueryableSource: class {
      )
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the property/aggregate to fetch and the series of queries for the request.
-     - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - returns: the result of the the query as specified by the `QueryChainableBuilderType`, or `nil` if no match was found.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func queryValue<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> B.ResultType? where B.ResultType: QueryableAttributeType
 
@@ -83,6 +86,7 @@ public protocol QueryableSource: class {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: QueryClause...) throws -> [[String: Any]]
 
@@ -95,6 +99,7 @@ public protocol QueryableSource: class {
      - parameter selectClause: a `Select<U>` clause indicating the properties to fetch, and with the generic type indicating the return type.
      - parameter queryClauses: a series of `QueryClause` instances for the query request. Accepts `Where`, `OrderBy`, `GroupBy`, and `Tweak` clauses.
      - returns: the result of the the query. The type of the return value is specified by the generic type of the `Select<U>` parameter.
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func queryAttributes<D>(_ from: From<D>, _ selectClause: Select<D, NSDictionary>, _ queryClauses: [QueryClause]) throws -> [[String: Any]]
     
@@ -120,6 +125,7 @@ public protocol QueryableSource: class {
      ```
      - parameter clauseChain: a `QueryChainableBuilderType` indicating the properties to fetch and the series of queries for the request.
      - returns: the result of the the query as specified by the `QueryChainableBuilderType`
+     - throws: a `CoreStoreError` value indicating the failure if the specified entity could not be found in any store's schema.
      */
     func queryAttributes<B: QueryChainableBuilderType>(_ clauseChain: B) throws -> [[String: Any]] where B.ResultType == NSDictionary
     

Sources/Select.swift

@@ -298,6 +298,9 @@ public enum SelectTerm<D: DynamicObject>: ExpressibleByStringLiteral, Hashable {
     }
 }
 
+
+// MARK: - SelectTerm where D: NSManagedObject
+
 extension SelectTerm where D: NSManagedObject {
     
     /**
@@ -366,6 +369,9 @@ extension SelectTerm where D: NSManagedObject {
     }
 }
 
+
+// MARK: - SelectTerm where D: CoreStoreObject
+
 extension SelectTerm where D: CoreStoreObject {
     
     /**