有点复杂 NSPredicate (IOS)ha
现在，我需要对 NSFetchRequest 使用谓词。
但这里的情况有点不同，因为谓词要经历两个嵌套对多关系。
例如，我的实体是这样的：
现在我需要获取一些月和周 ManagedObjects，但是要求是所需周或月中一天的事件数量多于一个。
换句话说，对于给定的周或月，如果其“天”关系的目的地上的任何一天至少有一个事件，则接受它。
所以这是一个嵌套的多对多关系，我不知道如何设置谓词字符串。
有两个麻烦：
我知道 ALL 和 ANY 关键字。但是@“ANY days.ANY events”可以是关键路径吗？或者应该如何？
如何判断事件关系至少指向一个Event对象。
[@"%K != nil",theCorrectKeypath] 有效吗？我担心“！= nil”不等于至少一个目标对象？
等待有人来帮助我。
非常感谢！
Now, I need to use a predicate for a NSFetchRequest.
But things here are a little different, since there are two nested to-many relationships for the predicate to go through.
For instance, my entities are like this:
Now I need to fetch some Month and Week ManagedObjects, but the requirement is that the amount of Events of a Day of the needed Weeks or Months is more than one.
In another word, with reference to a given Week or Month, if any Day on the destination of its "days" relationship has at least one Event, then take it.
So that is a nested to-many relationship, and I don't know how to set the predicate string.
There are two troubles:
I know ALL and ANY keyword. But could
@"ANY days.ANY events"be the keypath? Or how is it supposed to be?How to judge that the events relationship points to at least one Event object.
Would [@"%K != nil",theCorrectKeypath] work? I'm afraid of that "!= nil" does not equal to at least one destination object?
Waiting for someone to help me out.
Terribly thanks!
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我自己找到了答案。
还有另一种方法可以得到这个，因为我的条件，我可以只谓词合适的Events对象，并且从Events到Week或Month都是一对一的关系，
所以一旦我得到了符合条件的Events，
我就可以得到相应的 划分的周和月
按Event.date.thisWeek 或theEvent.date.thisMonth
。谢谢你们，
I found the answer my self.
There's another way to get this, because of my condition, I can just predicate the suitable Events objects, and all the way from Events to Week or Month are to-one relationship,
so once I got the eligible Events,
I can just get corresponding Weeks and Months by
theEvent.date.thisWeek or theEvent.date.thisMonth.
Thanks for your guys,