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

Overview

A deep copy involves copying managed objects and their relationships from one persistent store to another. Once an object has been copied, the relationships from its source object are walked to find related source objects. Those related source objects are then copied to the target store as required. Relationships in the source store are then replicated in the target store between the copied objects. As this cycle continues for each object, every relationship in all directions is eventually copied into the target persistent store. Needless to say, this is a CPU-intensive task and should only be run in the background.

Depending on an application’s data model, it may be more efficient to copy all objects in one pass and then reestablish ...