Fore xcode to load bundle

Question

The core data models are in a bundle which is added to main project. now i have to migrate core data to newer model. i have been following some example like this so i want to migrate database before any queries or import happen. so i placed the code in - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions but the bundle which contains core data models is not loaded at that time. getting hold of bundle says its not yet loaded. So I can't start the migration process.

how can i force it to load this bundle?

is it a good way to have the core data models in a separate bundle other then the main bundle?

edit:

- (NSManagedObjectModel*)objectModel
{
if (_objectModel)
    return _objectModel;

    NSString *bundlePath = [[NSBundle mainBundle] pathForResource:kDataManagerBundleName ofType:@"bundle"];
    NSBundle *bundle = [NSBundle bundleWithPath:bundlePath];

NSString *modelPath = [bundle pathForResource:kDataManagerModelName ofType:@"momd"];
_objectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:[NSURL fileURLWithPath:modelPath]];

return _objectModel;
}

for the migration part it says bundle not yet loaded and returns nil for pathForResource.

Answer 1

I ended up with moving the data model in main bundle as there is no way to load resources bundle on launching.

Answer 2

You can use the NSBundle method load to force to load a bundle (docs here). EDIT: As you said, this is only for executable code and not for resources.

About having CoreData models in a separate bundle, it's a common practice if you want to reuse that model(and/or any other resource) in several apps. If you don't want that there is no reason to have a separate bundle IMO.