How to remove objects if there is no other relationships in Core Data to this object?

Question

I have following entities in Core Data:

• PBOUser may have a lot of PBOLocation.
• PBOLocation may have a lot of PBOStatistics.
• PBOStatistics may belong to only one PBOLocation
• PBOLocation may belong to a lot of PBOUser

My relationship are described on the image below:

My problem:

I have userA with locationA and locationB and locationC I have userB with locationA and locationD

Now inside userA I assign a new NSSet with locationB.

What happens now?

• Do I remove locationC? (I really want that, because this location belongs ONLY to user being removed)
• Do I remove locationA? (I really do not want that, because that location belongs to other user: userB).

What should I do to achieve that result?

Answer 1

No locations are removed in described case, they just become orphaned. You should fetch locations and manually delete it before assign new set or implement special method to delete all orphaned locations.