Why am I getting a write error when copying a Core Data database between iPhone and iPad?

In my app I create and use a normal persistent store:

- (NSPersistentStoreCoordinator *) persistentStoreCoordinator {
    //  D_IN;   
    if (persistentStoreCoordinator != nil) {
        return persistentStoreCoordinator;
    }
    persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];

    // Allow inferred migration from the original ver开发者_如何学Gosion of the application.
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                             [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];

    NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"Dances005.sqlite"]];




    NSError *error = nil;

    if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl 
                                                        options:options error:&error]){
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);


    }
    //  D_OUT;

    return persistentStoreCoordinator;

..nothing special. It contains several NSData objects - all core data compliant on iPhone and iPAD.

I create the file on the iPhone and would like to copy it to the iPAD. When I open the same app on the iPAD it uses the copied sqlite and works fine as long as it reads/fetches. As soon as I change the data and need to store back I get the following error:

Unresolved error Error Domain=NSCocoaErrorDomain Code=256 UserInfo=0x6a2b7a0 "Operation could not be completed. (Cocoa error 256.)", {
    NSFilePath = "/var/mobile/Applications/294B329D-D287-4012-A551-4E7348624225/Documents/Dances005.sqlite";
    NSUnderlyingException = error during SQL execution : attempt to write a readonly database;

Currently I use iPhoneExplorer and just drag the file from iPhone -> MAC -> iPAD. I checked the rw Attributes with iFile and they are rw for the user on the iPAD. (same as on iPhone)

What could be the problem here and how can I solve this?

iPhoneExplorer is not supported by Apple and "just drag[ging] the file from iPhone -> MAC -> iPAD" is not supported. If you want to include the file on your iPad application then include it as part of the bundle or use another mechanism to transfer the file.