核心数据NSSet是否包含具有特定ID的对象？ [英] Does a Core Data NSSet contain an object with a certain ID?

问题描述

我有一个Core Data对象，包含其他对象的NSSet（例如，库对象包含书的NSSet）。检查库的实例是否包含具有某个bookID的书的最好方法是什么？

I have a Core Data object that contains an NSSet of other objects (e.g. Library object contains NSSet of Books). What's the best way to check if an instance of Library contains a book with a certain bookID?

可以使用Key Value编码完成，或者我必须枚举所有书籍并手动检查？

Is it possible to be done with Key Value coding or do I have to enumerate all books and check them manually?

推荐答案

是的，您可以使用KVC。

Yes, you can use KVC for this.

BOOL bookExists = [[set valueForKey:@"bookID"] containsObject:@"myBookID"];

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