自动生成谓词行模板的多对一键？ [英] Automatically generated predicate row templates for to-many key?

问题描述

在我的Core Data托管对象模型中，我有一个实体Foo，它与一个名为baz的实体Baz具有一对多关系（一对多的逆）。 Baz有一个名为tag的字符串属性。当我使用 [NSPredicateRowEditorTemplate templatesWithAttributeKeyPaths：[NSArray arrayWithObject：@baz.tag] inEntityDescription：FooDescription] 为NSPredicateEditor创建行编辑器，结果包含）一个行模板如

[Popup：baz.tag] [Popup：Contains | is | is | ||] [TextField]

当我从弹出窗口中选择Contains时，带有谓词的查询按预期工作。如果我选择任何其他弹出窗口（例如是），我得到以下错误：许多密钥不允许在这里。我可以使用 [NSPredicateRowEditorTemplate templatesWithAttributeKeyPaths：inEntityDescription：] 或者我必须手动构建行编辑器吗？

它看起来像自动生成的模板（使用 [NSPredicateRowEditorTemplate templatesWithAttributeKeyPaths：inEntityDescription：] ）不能产生正确的运算符。解决方案是使用 [NSPredicateEditorRowTemplate initWithLeftExpressions：rightExpressionAttributeType：modifier：operators：options：] 手动创建模板。对于给定的示例：

  id template = [[NSPredicateEditorRowTemplate initWithLeftExpressions：[NSArray arrayWithObject：[NSExpression expressionForKeyPath：@baz.tag ]] rightExpressionAttributeType：NSStringAttributeType modifier：NSAnyPredicateModifier operators：keywordOperators options：0]; 
  

In my Core Data managed object model, I have an entity Foo with a to-many relationship (with a to-many inverse) to entity Baz named baz. Baz has a string property named "tag". When I use [NSPredicateRowEditorTemplate templatesWithAttributeKeyPaths:[NSArray arrayWithObject:@"baz.tag"] inEntityDescription:FooDescription] to create the row editors for an NSPredicateEditor, the result contains (as expected) a row template like

[Popup: baz.tag] [Popup: Contains|is|is not|...] [TextField]

When I select "Contains" from the popup, a query with the predicate works as expected. If I choose any of the other popups (e.g. "is"), I get the following error: "to-many key not allowed here". Can I use [NSPredicateRowEditorTemplate templatesWithAttributeKeyPaths:inEntityDescription:] or do I have to build the row editor manually?

解决方案

It looks like the automatically generated template (using [NSPredicateRowEditorTemplate templatesWithAttributeKeyPaths:inEntityDescription:]) cannot produce the correct operators. The solution is to create the template manually using [NSPredicateEditorRowTemplate initWithLeftExpressions:rightExpressionAttributeType:modifier:operators:options:]. For the given example:

id template = [[NSPredicateEditorRowTemplate initWithLeftExpressions:[NSArray arrayWithObject:[NSExpression expressionForKeyPath:@"baz.tag"]] rightExpressionAttributeType:NSStringAttributeType modifier:NSAnyPredicateModifier operators:keywordOperators options:0];

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