How do I set up Core Data lightweight migration using MagicalRecord?

问题

I have hit a brick wall trying to setup lightweight migration of Core Data using MagicalRecord. I have looked at all of the posts on this subject, using Google and SO. I understand how the persistentStoreCoordinator works and what the settings I am trying to make also do.

Here's my code:

AppDeligate.h

NSPersistentStoreCoordinator *persistentStoreCoordinator;

AppDelegate.m

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {

if (persistentStoreCoordinator != nil) {
    return persistentStoreCoordinator;
}

NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"saori.sqlite"]];

// handle db upgrade
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                         [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];

NSError *error = nil;
persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];

if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:options error:&error]) {

    // Handle error
}

return persistentStoreCoordinator;

}

I'm getting the following errors, which I understand; what I don't know is where are these objects (I have looked in my app, and found nothing):

No visible @interface for 'AppDelegate' declares the selector 'applicationDocumentsDirectory' and

No visible @interface for 'AppDelegate' declares the selector 'managedObjectModel'

I have already created the stores:

Most, if not all of the code I have looked at is similar; I don't know if MagicalRecord handles this for me or not because I can't find any docs that would indicate how to do this using MR. My question is: what do I have to do to make this work?

回答1:

The whole point of MagicalRecord is that this is managed for you:

[MagicalRecord setupCoreDataStackWithAutoMigratingSqliteStoreNamed:####];

Check the docs about the Core Data stack setup here.

回答2:

Make sure you check all of these things:

In your AppDelegate.m file:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    ...
    [MagicalRecord setupAutoMigratingCoreDataStack];
    ...
}

If you haven't versioned your model already:

Select your data model

Editor -> Add Model Version
Name the new version, Finish

There should be two versions now. Select the file as shown.

Change the Model Version to your new version

The new version should be checked now

回答3:

As of my understanding of the question, i suggest you to use this

[MagicalRecord setupAutoMigratingCoreDataStack]

If you have not changed the model version, change it to new model created from the old model

来源：https://stackoverflow.com/questions/16841158/how-do-i-set-up-core-data-lightweight-migration-using-magicalrecord

标签

ios

core-data

magicalrecord