Don't do this using direct access to the SQLite database. CoreData does caching and its own indexing of the values it stores, which can involve keeping more than one copy of data in the database. If you want to update a CoreData database, do it using the CoreData API. Then you can be absolutely sure that your updates won't corrupt the database. And frankly it's no harder doing things that way than it is to learn SQLite if don't already know it.