托管对象未在我的核心数据库中正确删除 [英] Managed object not deleted properly in my core database

问题描述

我正在尝试从我的实体预订中删除​​一些对象。我这样做。

I am trying to delete some objects from my Entity Reservation. I am doing it like this.

NSManagedObjectContext *context = reservation.managedObjectContext;
[context deleteObject:reservation];
NSError *error = nil;
if (![context save:&error]) {
    NSLog(@"Error is %@",error);
}

之后，我删除了我的对象，获取整个实体。我可以看到对象是从我的实体删除。但是当我重新启动我的应用程序，我在上一次会话中删除的所有对象都存储在我的实体。

After that I delete my object I fetch the whole entity again. I can see that the object is delete from my entity. But when I restart my app, all my objects that I deleted in the previous session are back stored in my entity.

我使用 restkit 存储我从web服务返回的对象。此外，当我删除对象，我删除它也在我的数据库。

I'm using restkit to store my objects that I got back from a webservice. Also when I delete the object, I delete it also in my database.

当我重新启动我的应用程序，看看我的日志，我看到我没有从我的Web服务，我在上一个会话中删除的对象，所以这是oké 。唯一的问题是它们以某种方式存储在我的核心数据库中。

When I restart my app and look at my logs I see that I don't get the object back from my webservice that I deleted in the previous session, so that's oké. The only problem is that they are somehow stored back in my core database.

推荐答案

我不完全确定reskit如何处理线程上的保存/删除，但基本上当您在注册通知的主线程上设置NSManagedObjectContext。

I am not entirely sure how reskit handles saving/deleting on threads but basically when you setup your NSManagedObjectContext on the main thread you register for notifications.

-(NSManagedObjectContext *)aContext
{
   if (!_aContext) {
       _aContext = [(AppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
       [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mergeChanges:) name:NSManagedObjectContextDidSaveNotification object:nil];
   }
   return _aContext;
}

如果在后台线程上发生对上下文的更改， 。

If a change to context happens on a background thread then a notification will be sent.

-(void)mergeChanges:(NSNotification *)aNotification
{
 // Merge the changes from the notification
 // on the main thread as this is the main
 // context for our application.
 dispatch_async(dispatch_get_main_queue(), ^{

    [self.aContext mergeChangesFromContextDidSaveNotification:aNotification];
 });
}

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