Question

If I need to programmatically empty a NSSet automatically created by Core Data (multiple relationships), what should I do ? Something like this ?

[self willChangeValueForKey:@"MyRelationship"];

[[self MyRelationship] release];
[self MyRelationship] = [NSSet alloc] init];

[self didChangeValueForKey:@"MyRelationship"];

Not sure it is correct at all…
thanks

Answer 1

[[self mutableSetValueForKey:@"MyRelationship"] removeAllObjects];

For some reason, I can never get the “cascade” delete rule to work, so when I want the objects deleted as well I have to iterate over the set and call [self.managedObjectContext deleteObject:obj] or else I’ll get validation errors, if the relationship is defined as required.