Registering a Custom Store Type

To use a custom store type in an application, you must register the store type with the NSPersistentStoreCoordinator class using registerStoreClass:forStoreType:. The type name must be a unique string.

Typically you define the store type as a string constant:

// in MyAtomicStore.h

extern NSString *MY_ATOMIC_STORE_TYPE;

// in MyAtomicStore.m

NSString *MY_ATOMIC_STORE_TYPE = @"MyAtomicStore";

You should ensure that a type is registered before you try to add a store of that type to a persistent store coordinator. For example, in an application delegate in OS X you might register in applicationWillFinishLaunching:.

- (void)applicationWillFinishLaunching:(NSNotification *)aNotification

{

    [NSPersistentStoreCoordinator registerStoreClass:[MyAtomicStore class]

                                     forStoreType:MY_ATOMIC_STORE_TYPE];

}

In a document-based application, the type is the identifier NSPersistentDocument uses to associate a persistent store type with a document type (see persistentStoreTypeForFileType:).