应用重启后，核心数据会丢失

Question

问题：重启应用后，数据丢失; 我已经阅读了很多关于这个问题的主题，但似乎无法为我的案例找到解决方案。这是我的代码：

id appDelegate = (id)[[UIApplication sharedApplication] delegate];
self.managedObjectContext = [appDelegate managedObjectContext];


Car *newCar = [NSEntityDescription insertNewObjectForEntityForName:@"Car"
                                                   inManagedObjectContext:self.managedObjectContext];
newCar.name = self.nameTextField.text;
newCar.c02 = self.carbon.text;
newCar.norma = self.norma.text;
newCar.cc = self.centrimCubi.text;
newCar.age = self.vechime.text;
newCar.costTimbru = self.zaLabel.text;


[self.theCar.managedObjectContext save:nil];  // write to database

self.theCar = newCar;

新对象显示在tableview上，但直到我重新启动应用程序

为了检索我使用的数据：

- (void)setupFetchedResultsController
{
    // 1 - Decide what Entity you want
    NSString *entityName = @"Car"; // Put your entity name here
    NSLog(@"Setting up a Fetched Results Controller for the Entity named %@", entityName);

    // 2 - Request that Entity
    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:entityName];

    // 3 - Filter it if you want
    //request.predicate = [NSPredicate predicateWithFormat:@"Person.name = Blah"];

    // 4 - Sort it if you want
    request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"name"
                                                                                     ascending:YES
                                                                                      selector:@selector(localizedCaseInsensitiveCompare:)]];
    // 5 - Fetch it
    self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:request
                                                                        managedObjectContext:self.managedObjectContext
                                                                          sectionNameKeyPath:nil
                                                                                   cacheName:nil];
    [self performFetch];
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    [self setupFetchedResultsController];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Persons Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }
      // Configure the cell...
    Car *person = [self.fetchedResultsController objectAtIndexPath:indexPath];
    NSString *fullname = [NSString stringWithFormat:@"%@ € ", person.costTimbru];
    cell.textLabel.text = person.name;

    cell.detailTextLabel.text = fullname;

    //cell.textLabel.text = person.firstname;
       return cell;

}