为什么“不输入”不工作在这个NSPredicate？ [英] Why "NOT IN" does not work in this NSPredicate?

问题描述

A 。 b 和 B c $ c> a 是多对数关系。为什么 A 的此谓词有效：

  NSPredicate * predicate = NSPredicate predicateWithFormat：@NOT SELF IN％@，bObject.a]; 
  

，但这不：

  NSPredicate * predicate = [NSPredicate predicateWithFormat：@NOT％@ IN b，bObject]; 
  

我想两个谓词应该给出相同的结果 - A 与 bObject 通过 a < - > b 没有关系。

更新：

---

这里是一个示例项目，其中 A 。 b 体现为帐户。 filtered_clients 和 B 。 a 由客户 MasterViewController.m 切换第143行和第144行的注释。

看到差别。

请帮助我找到我的代码中的错误，或确认它是一个核心数据错误，报告给苹果。非常感谢。

解决方案

这里是另一个想法：也许是试图否定 bObject 与 NOT 。因此，请尝试：

  @NOT（％@ IN b）
  / pre> 
A.b and B.a are inverse to-many relationships. Why does this predicate for A work:
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"NOT SELF IN %@", bObject.a];
while this one does not:
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"NOT %@ IN b", bObject];
I think both predicates should give the same result — the collection of As that have no relation with bObject via a<-->b. But in fact, the first one gives the correct collection while the second one not.

Update:



Here is a sample project wherein A.b is embodied by Account.filtered_clients and B.a is embodied by Client.filtered_by.

Toggle commenting of line 143 and line 144 in MasterViewController.m to see the difference. 

Please help me either find the bug in my code, or confirm it is a Core Data bug so I can report it to Apple. Thanks very much.
解决方案
Here is another idea: maybe it is trying to "negate" the bObject with the NOT. Thus, try: 
@"NOT (%@ IN b)"


                        
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