问题描述
我已经创建了两个这样的上下文：
I have created two context like this:
// create writer MOC
_privateWriterContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
[_privateWriterContext setPersistentStoreCoordinator:_persistentStoreCoordinator];
// create main thread MOC
_managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
_managedObjectContext.parentContext = _privateWriterContext;
我有一个 NSFetchResultedController c $ c> _managedObjectContext 。
I have a NSFetchResultedController initiated with _managedObjectContext.
我知道这很奇怪，但我添加一个记录到父 _privateWriterContext ，我保存。
I know it is strange, but I am adding a record to the parent to _privateWriterContext, I am saving it.
令人惊讶的是，因此 FRC 会收到有关此事件的通知。为什么？我没有重置的孩子，或任何其他。我认为他们是独立的实体，只要孩子的上下文不会得到保存。
What is surprising is that child context and so FRC gets notified about this event. Why? I have not reset-ed child, or anything else. I thought they are independent entities as long as child context will not get saved.
在@pteofil文章我发现这行：
In @pteofil article I found this line:
..它被推送到持久存储（通过持久存储协调器），并且对连接到存储的所有上下文都可见。
.. it is pushed to the persistent store (via the persistent store coordinator) and becomes visible to all contexts connected to the store.
推荐答案
我强烈建议避免父子环境设置。我们的书详细介绍了为什么它们常常导致奇怪的行为：
I strongly recommend avoiding parent-child context setups. Our book goes into detail why they often lead to strange behaviour: https://www.objc.io/books/core-data/
短篇小说：他们并不像你认为的那样独立。
Short story: They're not as independent as you might think.
如果您需要多个单一上下文，请使用共享一个持久性存储协调器的多个上下文。
Use multiple context that share a single persistent store coordinator if you need more than a single context.
这篇关于奇怪的父/子NSManagedObjectContext现象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！