核心数据到多个NSPredicate与AND [英] Core data to-many NSPredicate with AND

问题描述

我正在尝试为即搜即得类型的搜索栏写一个查询。我想做的是查询Kind，并返回任何有一个LocalName的类型（'name'LIKE％@ AND localeIdentifier ==％@）。

<如果我只搜索名称（所以忽略localeIdentifier），我可以这样做：

  ANY本地化.name LIKE％@ 
  

我想要的是更像

 任何本地化（名称LIKE％@ AND localeIdentifier ==％@）
  

总而言之，搜索Kind，多对多关系localized中的任何一个项目都应该匹配name和localeIdentifier。

解决方案

你想要的是一个子查询。在谓词格式语法中：

  SUBQUERY（self.localized，$ x，$ x.name LIKE％@ AND $ x.localeIdentifier ==％@）。@ count> 0 
  

其中 SUBQUERY 在 self.localized 集合中匹配第三个参数中的谓词的实例。 种类此SUBQUERY表达式非空的实例（即 @count> 0 ）符合您所需的条件。

SUBQUERY表达式是在OS X 10.5中引入的。

I'm trying to write a query for the find-as-you-type search bar. What I want to do is query "Kind", and return any Kinds for which there is a LocalName with ('name' LIKE %@ AND localeIdentifier == %@).

If I'm only searching the names (so ignoring the localeIdentifier), I could do something like this:

ANY localized.name LIKE %@

What I want is something more like

ANY localized.(name LIKE %@ AND localeIdentifier == %@)

To sum up, searching "Kind", any one item in the to-many relationship "localized" should match both name and localeIdentifier.

Any ideas for the correct syntax of this?

解决方案

What you want is a subquery. In predicate format syntax:

SUBQUERY(self.localized, $x, $x.name LIKE %@ AND $x.localeIdentifier == %@).@count > 0

where the SUBQUERY expression returns a collection of instances in the self.localized collection that match the predicate in the third argument. Kind instances for which this SUBQUERY expression is non-empty (ie @count > 0) match your desired criteria.

The SUBQUERY expression was introduced in OS X 10.5.

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