Question

Is it ok to add ivars and methods to an instance of NSManagedObject?

By “extra”, I mean ivars that you don’t want serialized.

Do I just add them to my NSManagedObject subclass like any other class or do I have to take any extra precautions?

Answer 1

You can do exactly what you described. If the ivars aren’t in the entity description, they aren’t part of the underlying model. Core Data actually has explicit support for NSManagedObject attributes that aren’t persisted, though — they’re marked “transient”. If you do make custom ivars, though, you should remember to let go of the “extra” instance variables in didTurnIntoFault rather than dealloc like you would with a normal object.