在CoreData的UserInfo字典 [英] UserInfo Dictionaries on CoreData

问题描述

什么是苹果公司的核心数据文档的这一部分意味着什么？

What does this part of Apple core data documentation means?

用户信息字典

许多管理对象模型的实体元素，属性和关系都具有的相关用户信息字典。你可以把你想要的任何信息到用户信息的字典，作为键 - 值对。装进用户信息字典共用信息包括为获取财产使用的predicate一个实体版本的详细信息，和值。

Many of the elements in a managed object model—entities, attributes, and relationships—have an associated user info dictionary. You can put whatever information you want into a user info dictionary, as key-value pairs. Common information to put into the user info dictionary includes version details for an entity, and values used by the predicate for a fetched property.

据我所知，在默认情况下的实体有字典，但我无法找到找到USERINFO上coredata实体或属性。

I understand that by default entities have that dictionary, but I'm not able to find find userInfo on coredata entities or attributes.

推荐答案

获得 NSEntityDescription 从 NSManagedObject （通过实体属性）或从 NSManagedObjectModel 并通过attributesByName得到NSAttributeDescription。这给了你，你得到的名字正确的描述，有 USERINFO 作为一个属性为好。

Get the NSEntityDescription from your NSManagedObject (through the entity property) or from your NSManagedObjectModel and get the NSAttributeDescription through attributesByName. This gives you a dictionary where you get the proper Description by name which has the userInfo as a property as well.

NSManagedObject *managedObject;
NSEntityDescription *entityDescription = managedObject.entity;
NSAttributeDescription *attributeDescription = entityDescription.attributesByName[@"someAttribute"];
NSString *foo = attributeDescription.userInfo[@"foo"];

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