Exception thrown in NSOrderedSet generated accessors

Question

On my Lion app, I have this data model:

The relationship subitem

Answer 1

Robert,

I agree your answer will work for this, but keep in mind that there is an automatically created method for adding a whole set of values to a relationship already. Apple's Documentation (as seen here under the "To-many Relationships" section or here under the "Custom To-Many Relationship Accessor Methods" section) implements them this way:

- (void)addEmployees:(NSSet *)value
{
[self willChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueUnionSetMutation
      usingObjects:value];
[[self primitiveEmployees] unionSet:value];
[self didChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueUnionSetMutation
      usingObjects:value];
}

- (void)removeEmployees:(NSSet *)value
{
[self willChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueMinusSetMutation
      usingObjects:value];
[[self primitiveEmployees] minusSet:value];
[self didChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueMinusSetMutation
      usingObjects:value];
}

You could easily compile your set of relationships outside of core data and then add them all at once using this method. It might be less ugly than the method you suggested ;)