CoreData错误：+ entityForName：找不到实体名称的NSManagedObjectModel [英] CoreData error: +entityForName: could not locate an NSManagedObjectModel for entity name

问题描述

我一直在努力与 CoreData 几天，但我一直收到这个错误：

I've been struggling with CoreData for a few days, but I keep getting this error:

'NSInternalInconsistencyException'，原因：'+ entityForName：找不到实体名称的NSManagedObjectModel。

'NSInternalInconsistencyException', reason: '+entityForName: could not locate an NSManagedObjectModel for entity name.

我已经检查了实体名称以及我在代码上写了什么，他们是一样的。我也重新创建对象数据模型，甚至从模拟器中删除应用程序，但没有什么似乎解决它。
这是我有：

I have checked the entity name and what I wrote on my code and they're the same. I also recreated the object data-model and even delete the app from the simulator but nothing seems to fix it. Here's what I have:

方法保存到CoreData中：

method to save into CoreData:

-(IBAction)save:(id)sender {
    NSManagedObject * newNews = [NSEntityDescription insertNewObjectForEntityForName:@"NewsStand"
    inManagedObjectContext:coredata.managedObjectContext];
    [newNews setValue:news_title forKey:@"story_title"];
    [newNews setValue:news_desc forKey:@"story_desc"];
    [newNews setValue:news_image  forKey:@"story_image"];
    [newNews setValue:test  forKey:@"story_url"];
    [coredata commit];
    NSLog(@"data saved!!!!");
}

我已经在一个单独的类中实现了核心数据的所有方法：

I have implemented all methods of core data in a separated class:

applicationDocumentsDirectory,  
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator, 
- (NSManagedObjectModel *)managedObjectModel, 
- (NSManagedObjectContext *)managedObjectContext

推荐答案

它有三个原因：

1. 拼写实体名称例如 NewsStand 而不是 NewsStands 。


2. li>
   
3. 加载了没有或错误的托管对象模型。

1. Misspelling the entity name e.g. NewsStand instead of NewsStands.
2. Having a nil managed object context
3. Having no or the wrong managed object model loaded.

（1）是最常见的，但（3）比（2）更常见。您可以检查您正在使用键入加载正确的模型：

(1) is the most common but (3) is more common than (2). You can check that you are loading the right model with the keypath:

aManagedObjectContext.persistentStoreCoordinator.managedObjectModel.entities

然后检查实体的名称。

then check the entity's names.

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