在核心数据文档中存储文档特定设置的最佳方法是什么？
我在应用程序中使用由 Core Data 支持的 NSPersistantDocument。
每个文档都有许多仅与该文档相关的设置。 例如，文档需要保存地址簿组的唯一 ID，以便稍后更新。
我考虑解决这个问题的方法是使用另一个模型 DocumentSetting，它有两个属性： 一个键和一个值，其中包含 NSString 。
理想情况下，我想要类似于 NSUserDefaults 但存储在文档中的内容。
以前有人这样做过吗？ 有没有更好的方法来解决这个问题？
I'm using a NSPersistantDocument backed by Core Data in my application.
Each document has a number of settings that are only relevant to that document. For example the document needs to hold the unique ID of an Address Book Group, to update it at a later date.
The way I'm thinking of approaching this is to have another model, DocumentSetting, which has two attributes; a key and a value, which hold NSString's.
Ideally I would like something similar to NSUserDefaults but stored within the document.
Has anyone done this before? Are there any better way to approach this?
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NSPersistentStore 上的 setMetadata: 方法可用于存储每个文档的设置。 有关如何使用商店元数据的文档可以找到 此处。 不过，正如文档中所建议的，可以放入其中的内容有一些大小限制。 如果您需要存储比几个键/值对更重要的内容，我建议您在数据模型中创建一个新实体来存储此类数据。
The setMetadata: method on NSPersistentStore can be used to store per-document settings. The docs for how to go about using the store's metadata can be found here. As advised in the docs though, there are some size limitations on what can be put in there. If you need to store something more substantial than a few key/value pairs, I would recommend making a new entity in your data model to store such data.
正如 Brian 所说，持久存储的元数据是进行此类操作的好地方。 或者，您添加单独实体的想法也可以工作（我过去使用过这两种方法）。 请记住，如果此
DocumentSetting实体与文档模型中的其他实体没有关系，您可以将其放入单独的 xcdatamodel 中，并使用-[NSManagedObjectModel mergedModelFromBundles 在运行时合并模型:]。 至少这样你可以让你的“源”模型文件保持一定的隔离。在策略方面，除非您将拥有大量此类文档设置或想要单独查询它们，否则您可以使用可转换属性并在您的
中存储（已存档的）实体。 这会让感觉更像NSDictionary>DocumentSettingsNSUserDefaultsAPI，它基本上就像一本字典。As Brian says, the persistent store's metadata is a good place for this kind of thing. Alternatively, your idea to add a separate entity work as well (I've used both methods in the past). Keep in mind that if this
DocumentSettingentity doesn't have relationships to other entities in your document model, you can put it into a separate xcdatamodel and merge the models at runtime using-[NSManagedObjectModel mergedModelFromBundles:]. At least this way you can keep your "source" model files isolated a bit.In terms of strategy, unless you are going to have a very large number of these document settings or want to query them individually, you could use a transformable property and store an (archived)
NSDictionaryin yourDocumentSettingsentity. This would make the feel much more like theNSUserDefaultsAPI which feels basically like a dictionary.