Using Core Data Concurrently and Reliably

Question

I\'m building my first iOS app, which in theory should be pretty straightforward but I\'m having difficulty making it sufficiently bulletproof for me to feel confident submittin

Answer 1

The main issue I've had with multi-threaded core data is inadvertently accessing a managed object in a thread/queue other than the one it was created in.

I've found a good debugging tool is add NSAsserts to check that to managed objects created in your main managed object context are only used there, and ones created in a background context aren't used in the main context.

This will involve subclassing NSManagedObjectContext and NSManagedObject:

• Add a iVar to the MOC subclass and assign to it the queue it was created on.
• Your MO subclass should check the current queue is the same as its MOC's queue property.

It's only a few lines of code, but long term can prevent you making errors that are hard to track down otherwise.