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

Migration Manager

Instead of letting a persistent store coordinator perform store migrations, you may wish to use a migration manager. Using a migration manager gives you total control over the files created during a migration and thus the flexibility to handle each aspect of a migration in your own way. One example of a benefit of using a migration manager is that you can report on the progress of a migration, which is useful for keeping the user informed (and less cranky) about a slow launch. Although most migrations should be quite fast, some large databases requiring complex changes can take a while to migrate. To keep the user interface responsive, the migration must be performed on a background thread. The user interface has to be responsive ...