我可以对NSFetchRequest应用多个谓词吗？最好手动解析我的结果吗？ [英] Can I apply multiple predicates to an NSFetchRequest? Would it be better to manually parse my results?

问题描述

Ok我有一个基本的iPad应用程序要求用户的5个搜索/过滤条件。基于这些数据，我需要转到我的核心数据db，并拉出符合该标准的任何受管对象。似乎我需要应用多个谓词到同一个请求，是可能吗？或者我可以写一个真正长的花哨谓词？有多种要求？我应该如何处理？

Ok I have a basic iPad app that asks for 5 search/filter criteria from the user. Based on this data, I need to go to my core data db, and pull out any managed objects that fit that criteria. It seems like I need to apply more than one predicate to the same request, is that possible? Or could I just write a really long fancy predicate? With multiple requirements? How should I approach that?

这是一个好主意，通过抓取请求抓住所有实体，然后循环遍历每个数组，并抓住任何对象，我发现符合我的搜索条件？

Would it be a good idea to just grab all the entities through the fetch request, and then loop through each array and grab any objects that I find that fit my search criteria?

请指教！

推荐答案

您正在寻找复合谓词，这里有一个AND谓词的示例：

Yes it's possible. You're looking for compound predicates and here's an example with AND predicates:

NSPredicate *compoundPredicate 
   = [NSCompoundPredicate andPredicateWithSubpredicates:[NSArray of Predicates]];

您也可以使用 notPredicateWithSubpredicates 和<$

链接到文档 http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSCompoundPredicate_Class /Reference/Reference.html

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