I have a data model for Formula 1 races with 3 entities:
If I generate
NSManagedObject subclasses to represent these entities, the code generated doesn't represent at all this design:
NSManagedObjectinstead of Team
Is this the expected behaviour? Am I supposed to fix the code generated by Xcode? Am I missing something?
BTW, I'm using Xcode 4.3.3
Core Data at the core is an object relational mapping library. Long time ago it was called Entreprise Object Framework, part of WebObjects.
So yes, the base object for any persistant object managed by Core Data is
NSManagedObject, and you can do whatever you want with them.
In your example, Team and Pilot will share a common table, and you'll be able to use queries to retrieve Teams and Pilots at once. That's the idea.
The Objective-C inheritance tree (if you use custom classes) can mirror the model you defined, but it doesn't need to. You can create a custom
RacingActor class, use it as a base class for custom
Pilot classes, or you can tell the model to use
Pilot objects. You can even define a completely unrelated base class (provided
NSManagedObject is a parent, directly or indirectly) for
Team and / or
Pilot if you want to.
You are then free to implement the specific behaviors you need in your business logic, either in controllers or in custom data classes.