CoreData is quite annoying when it comes to updating the database...
If the application has already been released in the app store and you need for the version 2.0 to update some entity/table in the database. You now end up with a database which is incompatible with the version 1.0 of you app.
Sadly by default, the code bail out spewing an error saying that the data you're trying to load doesn't match the existing model.
What's the best way to deal with the issue?
I think what you need to do is create Core Data versioning. I am personally using Sensible TableView for my Core Data applications and I think it's handling all this stuff automatically.