database - Swift - 从数据库中删除单条记录

Question

我正在尝试从数据库中删除一条记录。

if let items=fetchedResult{
            print(items.count) //this always prints "1", so it's working well
            for item:NSManagedObject in items{
                println(item) //this prints the only element found. Also working well
                println(sender.view!.restorationIdentifier!) //the restorationIdentifier matches with the id from the object in the database. Also working well
                managagedContext.deleteObject(item) //<-- THIS is what is not working
                sender.view?.removeFromSuperview() //removing the view well
            }
        }else{
            print("Could not delete \(error), \(error!.userInfo)")
        }

如评论中所述，行 managagedContext.deleteObject(item) 不起作用，我没有收到任何错误，它只是没有删除数据库中的对象。

我已经搜索了 2 天，但一无所获。我希望你能帮助我。

谢谢。

Answer 1

Apple's doc对于 deleteObject

Specifies an object that should be removed from its persistent store when changes are committed.

您需要调用context.save 来使您的更改持久化。 save documentation says that:

If a context’s parent store is a persistent store coordinator, then changes are committed to the external store

还有:this SO answer显示调用 save: 和管理 NSError 的详细信息