if (![ctx save:&error]) {
    NSLog(@"Failed to save to data store: %@", [error localizedDescription]);
    NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey];
    if(detailedErrors != nil && [detailedErrors count] > 0) {
        for(NSError* detailedError in detailedErrors) {
            NSLog(@"  DetailedError: %@", [detailedError userInfo]);
        }
    } else {
        NSLog(@"  %@", [error userInfo]);
    }
}