How to add database layer in core data application

I am fairly new to core data technology and i searched a lot on how to add the databa开发者_运维百科se to a core data application.so can anybody guide me on how to integrate the database layer? i have seen the iphone tutorial on core data (i.e books example) but i am not able to understand how to .sqlite file has been included in that application

The SQLLite file is automatically generated at startup by core data, by the persistent store manager.

If you have a project generated to start with Core Data, look in the App Delegate at the persistentStoreCoordinator method - that's where it manages the file created and sets the path where it will exist. If there's an existing one it will make use of it, though you'd have to copy over a pre-loaded one into the writable path it sets up for the database.

Core Data is NOT a database, it is a persistent object store. You have no control over how the data is stored in the file. (So trying to get it to use your own designed database is a bad idea.) You only get to chose wether it uses XML, binary or sqlite as its backstore.

To see how your app gets the data from the file, look in the app delegate. (That is where most sample code put it.) You'll find some methods for the managed object context, and the persistent store coordinator. The latter will create the file if needed. Besides the save call during quit, or other relevant times, you don't have to do much with it. (You can do some stuff, but I can't recommend that when you're new to Core Data.)