Exception thrown in NSOrderedSet generated accessors

Question

On my Lion app, I have this data model:

The relationship subitem

Answer 1

I have had the same problem, but only when I tried something different to what I had been doing. I can't see the code for subItem, but I will assume that it has a reverse link to item. Lets call this reveres link, "parentItem", then the easiest solution is this:

Item *item = [NSEntityDescription insertNewObjectForEntityForName:@"Item" inManagedObjectContext:self.managedObjectContext];
item.name = @"FirstItem";

SubItem *subItem = [NSEntityDescription insertNewObjectForEntityForName:@"SubItem" inManagedObjectContext:self.managedObjectContext];

//[item addSubitemsObject:subItem];
subItem.parentItem = item;

The effect is that it makes use of apple's own code and it is simple and clean. In addition, the set is automatically added to, and all observers are updated. No problem.