核心数据原语访问器 [英] Core Data Primitive Accessors

问题描述

我有点困惑的是，Core Data是否以setPrimitiveAttributeName：形式为NSManagedObject子类生成原始访问器，与setPrimitiveValue：forKey :,形式一致。

I'm a little confused by whether Core Data generates primitive accessors for NSManagedObject subclasses in the form setPrimitiveAttributeName:, as compared to the form setPrimitiveValue: forKey:, which it seems to do consistently.

我的困惑的根源是我已经使用建模工具（XCode 4）为我的两个实体生成NSManagedSubclasses，据我所知，共享相同的元数据设置，子类识别setPrimitiveAttributeName形式，而另一个没有（它给我一个未找到方法编译器警告）。

The source of my confusion is that I have used the modeling tool (XCode 4) to generate NSManagedSubclasses for two of my entities, which, as far as I can tell, share the same metadata settings, yet one subclass recognizes the setPrimitiveAttributeName form, whereas the other doesn't (it gives me a "method not found" compiler warning).

那么，期望是什么？如果我打开一个新项目，创建一个实体与一个属性，并使用建模工具生成必要的NSManagedObject子类代码，我应该期望它自动生成更高效的形式的原始访问器吗？

So, what is the expectation? If I open up a new project, create one entity with one attribute, and use the modeling tool to generate the necessary NSManagedObject subclass code, should I expect it to auto-generate the more efficient form of the primitive accessor or not?

推荐答案

我遇到了类似的问题。而运行时生成原始访问器，Xcode 4不会为原语生成声明的属性，您必须在子类中根据文档自己执行此操作。

I've been running into a similar problem. While the runtime generates the primitive accessors, Xcode 4 does not generate the declared properties for primitives, you have to do this yourself in the subclass, per the docs.

我个人为每个Entity创建一个类别，并且总是把我的自定义代码放在那里，这样我就可以在需要时重新生成MO，而不必复制和粘贴。

I personally create a category for every Entity and always put my custom code in there, that way I can regenerate the MOs whenever I want and not have to copy and paste.

您可以在类别中执行此操作，界面包含：

You can do this in a category, the interface has this:

@property (nonatomic, retain) NSDate * primitiveLastUsed;

其实现方式如下：

@dynamic primitiveLastUsed;

相当光滑，使来自Xcode的MO无法再生。

Pretty slick, makes regenerating MOs from Xcode painless.

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