“SwiftData inheritance relationship”

I have the exact same issue and just filed a report FB15146262. iOS 18 doesn't set the one-to-many relationship from the 'one' side, i.e. setting student.school = school will actually keep the relationship at nil and can't be saved into context. This is visible in the debugger error message: SwiftData.DefaultStore save failed with error: Error Domain=NSCocoaErrorDomain Code=1570 %{PROPERTY}@ is a required value. UserInfo={NSValidationErrorObject= (entity: Student; id: 0x600000223380 x-coredata://3B392729-2729-4812-B567-647032714A50/Student/t6F58A598-9DC2-4927-A418-8D37D760FC072; data: { name = jack; school = nil; }), NSLocalizedDescription=%{PROPERTY}@ is a required value., NSValidationErrorKey=school, NSValidationErrorValue=null} The workaround by @Rainbowql with additionally calling append fixes this issue on iOS 18 but causes the app to crash on iOS 17, because the relationship is already set normally before calling append. On iOS 17, you will get: SwiftData/PersistentMo

And last question…In line 20 numberOfSides is literally initialized to 4 (how come, again, it does not have the override keyword, if it's changing the initializer/value from 0 from line 2, to the value of 4?Here also, not an override, you just set the value in the instance of the subclass.So line 20 does not change the value in the superclass. This is a basic principle of inheritance.Logic is:class NamedShape sets a default value of 0 for numberOfSidesWhen you init a Square withclass Square: NamedShape { var sideLength: Double init(sideLength: Double, name: String) { self.sideLength = sideLength super.init(name: name) print(Square inherited numberOfSides, numberOfSides) numberOfSides = 4 }after initializing all properties of the subclass (sideLength, as it was not defined with a default value), you initialize all the properties inherited from super class. super.init means you use the initializer defined in super class.At this point, numberOfSides is 0, for the subclass instance I have added

I managed to create a minimal repro example: import SwiftData import SwiftUI @Model final class ParentModel { var name: String @Relationship(deleteRule: .cascade, inverse: ChildModel1.parent) var children: [ChildModel1]? @Relationship(deleteRule: .cascade, inverse: ChildModel2.parent) var children2: [ChildModel2]? init(name: String) { self.name = name } } @Model final class ChildModel1 { var name: String @Relationship(deleteRule: .nullify) var parent: ParentModel? init(name: String) { self.name = name } } @Model final class ChildModel2 { var name: String @Relationship(deleteRule: .nullify) var parent: ParentModel? init(name: String) { self.name = name } } struct ContentView: View { @Environment(.modelContext) private var modelContext var body: some View { List { Button(Create parent with children) { createParentWithChildren() } Button(Delete) { delete() } } } func createParentWithChildren() { let parent = ParentModel(name: Parent) let child1 = ChildModel1(name: Chi

Why sad from inheriting from the correct class?