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

Using the Default Data Store as the Initial Store

A persistent store full of default data has been created by Core Data as a part of the XML import. Core Data created the database so the format will be correct. To set a default store as the initial store, the database file needs to exist in the application bundle. When preparing a default database to ship with your application, you’ll need to take into account the database journaling mode. Since iOS 7, a new default journaling mode called Write-Ahead Logging (WAL) has been set for SQLite databases. This new default increases performance and provides better concurrency support. As a side effect, there are now three files per database by default:

The sqlite file is the database file, as per usual. ...