Learning Core Data for iOS: A Hands-On Guide to Building Core Data Applications

4. Managed Object Model Expansion

Black holes are where God divided by zero.

Albert Einstein

In Chapter 3, “Managed Object Model Migration,” you learned how to manage a changing model with versioning, mappings, and migration techniques. This chapter will exercise your newfound migration knowledge as it introduces further changes to the model. The topics will cover expanding beyond one or two entities with the introduction of relationships, and at the end of the chapter, entity inheritance. The implications of delete rules will be discussed, along with the impact some of them can have on data validation. Following that, you’ll be shown how to handle data validation errors and, worst case, how to terminate gracefully and give users an error code ...