restrict delete of a referenced managedobject

Question

I have a simple Core Data model:

Entity Team (name, logo) Entity Sport (name, teams to->many Teams)

So, a Sport can have many Teams

I create the Team first, then add or edit a Sport and add the Teams. If I delete a Team, my app starts crashing. I believe because it is looking for the deleted reference.

So, how can I restrict via Core Data, not to delete an Entity which is being used as reference from another Entity's relation.

I don't want to set the relationship to nil. And I don't want to go and delete the Team from the Sport first, and then delete it alone. I just want it to notify that I can't delete it. i.e. I'm looking for a built-in checker.

Answer 1

You might want to read up on Core Data's "Relationship Delete Rules", if you haven't already. And you want to make sure that your Team <<---> Sport relationship is bidirectional.

Alternatively, instead of calling the generated removeXxxObject and removeXxxs methods directly, you may want to implement wrapper methods that do necessary checking before calling 'remove' methods.