On Jun 28, 2011, at 08:40, Brad Stone wrote:
> I get the below. Notice the new SRTodoEntity is properly in the todos
> relationship but there's also a reference to it outside of the SRNoteEntity.
> Intuitively, I would think there should be only one reference to it inside
> SRNoteEntity. This is my confusion. Why is it reference twice? How can I
> prevent that from happening if this isn't normal?
>
> po [[self managedObjectContext] registeredObjects]
> {(
> <Note> uid:330961758011065
> creationDate:2009-09-05 13:21:54 -0400
> modificationDate:2009-09-06 12:41:02 -0400
> todos:Relationship objects for {(
> <SRTodoEntity: 0x200483d80> (entity: SRTodoEntity; id: 0x2004121e0
> <x-coredata://614245CF-F03E-4F43-9D7F-98CDCB2899FA/SRTodoEntity/p1> ; data: {
> note = "0x2002c4e60
> <x-coredata://614245CF-F03E-4F43-9D7F-98CDCB2899FA/SRNoteEntity/p1>";
> todoViewData = nil;
> })
> )} on 0x200448360
> noteData:538
>
> <SRTodoEntity: 0x200483d80> (entity: SRTodoEntity; id: 0x2004121e0
> <x-coredata://614245CF-F03E-4F43-9D7F-98CDCB2899FA/SRTodoEntity/p1> ; data: {
> note = "0x2002c4e60
> <x-coredata://614245CF-F03E-4F43-9D7F-98CDCB2899FA/SRNoteEntity/p1>";
> todoViewData = nil;
> })
> )}
You've kinda got hold of the wrong end of this. Core Data is an object graph,
certainly, and any pointer to a managed object is a "reference" to the object.
There are references to these objects all over your code -- every stack
variable pointer is a reference. In the above example, a reference to the Todo
object exists inside the set of references that represents Note's relationship
to its Todo's. That makes it a really important reference, but it's certainly
never the only one.
By sending a 'registeredObjects' message to the managedObjectContext (which is
*not* an object in the object graph), you've asked it to construct a collection
(a set, as it happens) of references to Core Data objects it knows about.
There's no *relationship* from the MOC to the managed objects, it's just the
MOC's job to know what managed objects are currently in memory.
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