How to sort by relationship? #110

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2025-12-29T15:24:47+01:00

adam commented

2025-12-29 15:24:47 +01:00

Originally created by @ghost on GitHub (Dec 13, 2016).

I have an entity Person, each person has many messages. I wish to sort my tableview based on the last message's timestamp per each Person. Essentially, accomplish something like this .
let People: ListMonitor = {

          return Static.datastack.monitorSectionedList(
        
               From<Person>(),
               SectionBy(#keyPath(Person.section)),
               Where("messages.@count > 0"),
               OrderBy(.descending(#keyPath(Person.messages.last.timestamp))) <--------
        
    )
    
}()

Originally created by @ghost on GitHub (Dec 13, 2016). I have an entity Person, each person has many messages. I wish to sort my tableview based on the last message's timestamp per each Person. Essentially, accomplish something like this . let People: ListMonitor<Person> = { return Static.datastack.monitorSectionedList( From<Person>(), SectionBy(#keyPath(Person.section)), Where("messages.@count > 0"), OrderBy(.descending(#keyPath(Person.messages.last.timestamp))) <-------- ) }()

adam added the question label 2025-12-29 15:24:47 +01:00

adam closed this issue

2025-12-29 15:24:47 +01:00

adam commented

2025-12-29 15:24:48 +01:00

@JohnEstropia commented on GitHub (Dec 14, 2016):

Unfortunately, Core Data doesn't support sorting lists with relationships. My suggestion is to add a messageCount attribute in the Person entity which you update whenever a message is added to a person. You can then use that attribute to sort.

@JohnEstropia commented on GitHub (Dec 14, 2016): Unfortunately, Core Data doesn't support sorting lists with relationships. My suggestion is to add a `messageCount` attribute in the `Person` entity which you update whenever a message is added to a person. You can then use that attribute to sort.

adam commented

2025-12-29 15:24:48 +01:00

@ghost commented on GitHub (Dec 15, 2016):

Thank you John, just making sure I wasn't missing out on a feature. I guess that should work !

@ghost commented on GitHub (Dec 15, 2016): Thank you John, just making sure I wasn't missing out on a feature. I guess that should work !

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prototype/swift6

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prototype/concurrency

minIOS13

prototype/containers

transactionSourceTracking

prototype/swiftui

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swift5_3

prototype/propertyWrapperFields

prototype/propertyWrappers

prototype/propertyWrapper

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prototype/Swift_4_1

prototype/Swift_4_0

prototype/Swift_3_2

prototype/queryBuilders

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Reference: starred/CoreStore#110