On Mon, Jun 15, 2009 at 2:56 AM, Quincey Morris<quinceymor...@earthlink.net> wrote:
> What implementation of the 'tag' and 'book' properties are you using? (That > is, how are setTag and setBook defined?) I am just using @property and @dynamic to define all of these. SCBook.h: @property (nonatomic, retain) NSSet *tags; // This is the Book->BookTag relationship. SCBook.m: @dynamic tags; SCBookTag.h: @property (nonatomic, retain) SCBook *book; @property (nonatomic, retain) SCTag *tag; SCBookTag.m: @dynamic book; @dynamic tag; SCTag.h: @property (nonatomic, retain) NSSet *bookTags; SCTag.m: @dynamic bookTags; > (It's a bit confusing, btw, that you've called the Book->BookTag > relationship 'tags' instead of 'bookTags'.) Sorry. I'd change how I talk about them now but I fear that would just lead to more confusion. > You should double check that everything is correctly defined in your managed > object model. Make sure, for example, that it shows that the inverse > relationships are recognized as inverses. Also, check any validation > conditions on your attributes. For example, if your Book->BookTags to-many > relationship has a cardinality range of 0-1, you probably aren't going to > get the results you expect. Yeah, I initially had the same thought and I have checked and double checked the data model. The inverses all look good, and all the validation conditions are very lax. The only one I have set is to ensure that a Tag must have at least one BookTag under the bookTags relationship. > However, based on your description, it actually sounds more like you have a > memory management problem. Are you using garbage collection? If not, are you > sure you're retaining objects appropriately? I am not using garbage collection. Do I actually need to retain anything in the code example in my original message? From creating the SCBook to calling [[book tags] count] I am not retaining anything, but I was under the impression that I did not have to since this would all happen before the autorelease pool empties itself. I went ahead and tried retaining all of them in my example and [[book tags] count] is still 1. > Whatever gives you an actual error message is your best attack point for > solving your problem. Yeah, I spent hours tying to determine why I was getting a "dangling reference to an invalid object" error when deleting an existing BookTag and adding a new BookTag in the same commit. I kept trying to simplify the scenario and then started to notice that even the initial creates were not acting as I expected. I eventually decided that adding two BookTags was still causing me to scratch my head, and because that seemed like a really simple scenario, I thought I would start there. Do you have any suggestions for how I would approach the dangling reference error? It points to the BookTag object I deleted (both Book and Tag in that object point to nil). I definitely call [managedObjectContext deleteObject:bookTag] but I guess that somehow, somewhere in the object tree someone still has a reference to it. It was this that caused me to think that my model was incorrect in how the object tree is constructed. > You can use the debugger to examine your object relationships. When you add > the second object to the relationship (from either end), are the first > object's relationships getting clobbered, or are the second objects > relationships not being set up properly? The debugger is telling me that all of the relationships look fine except for the Book->BookTags relationship. The set of BookTags only contains the first BookTag object I created (scifi, in my example). The 'dystopian' tag, on the other hand, is not there. However, the relationships all look fine in the tag2 and bookTag2 objects. bookTag2 points at both the book and tag2, and tag2 points at bookTag2. It's all very strange. > You can also try calling [moc processPendingChanges] before checking to see > if the desired inverse relationships were set up. I don't recall ever having > to use it in such circumstances, but I may be misremembering the sequence of > events. Yeah, I did try calling that before [[book tags] count], but sadly it made no difference. Thank you very much for the time you have spent helping me thus far. This issue is really killing me. - Sebastian _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
