re: Strange Core Data save behaviour ("required relationship nil"... when it is set the line before saving)
re: Strange Core Data save behaviour ("required relationship nil"... when it is set the line before saving)
- Subject: re: Strange Core Data save behaviour ("required relationship nil"... when it is set the line before saving)
- From: Ben Trumbull <email@hidden>
- Date: Tue, 29 Sep 2009 18:59:58 -0400
Now, I have some code that changes the value of the 'B enumeration
value' that A is using. This does the following:
1. Create a new instance of the B subentity that represents the value
we want (in the same MOC as A)
2. Delete the old B object that A was pointing to, i.e. [moc
deleteObject:B];
3. Set A's to-one relationship to point to the new B object (and for
good measure, set B's inverse relationship - though this should be
done automagically).
4. Save the moc
4. is where badness happens (failed to save). The error tells me that
A's relationship property to B is nil... but just before I do the save
I log the value of the object referenced by this relationship and it's
the new 'B' object!
I have no idea what I've done to upset Core Data such that it claims a
relationship is nil when I save, but the line before the [moc
save:&err], the relationship shows as referencing a perfectly good
object.
So you delete B, which has an inverse relationship to A. Then you set
a new B on A. Then you save, and delete propagation cleans up the
graph, nullifying the old B's inverse relationship ?
What happens if you add a call to -processPendingChanges in between #2
and #3 ?
- Ben
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