XSD 1.1 条件类型分配<alternative test=“">检查元素是否没有设置属性? [英] XSD 1.1 Conditional Type Assignment <alternative test=""> to check if an element hasn't an attribute set?

问题描述

我想问一下是否有人知道如何进行 XSD 1.1 条件类型分配检查元素是否没有使用 XPath 查询的属性，例如:

<元素名称="TimeTravel" type="TravelType"><alternative test="@direction='Future'"><复杂类型><复杂内容><restriction base="TravelType"....<!-- 一些过去旅行相关的元素放在这里--></complexType></替代方案><alternative test="@direction='Past'"><复杂类型><复杂内容><restriction base="TravelType"....<!-- 一些未来旅行相关的元素在这里--></complexType></替代方案></元素>或者<!--命名的替代类型定义--><元素名称="TimeTravel" type="TravelType"><alternative test="@direction='Future' type="FutureTravelType"/><alternative test="@direction='Past' type="PastTravelType"/></元素>

在此示例中，'alternative test=""' 检查 TimeTravel 元素的属性direction"是否具有Future"或Past"值.我应该如何编写 XPath 查询来检查例如当前元素没有方向"属性?

解决方案

XPath "@direction" 将测试方向的存在当前元素上的 code> 属性:

XPath "not(@direction)" 将测试当前元素上 direction 属性的缺失:

另请注意，可以完全省略 alternative/@test 属性以提供默认类型.

更新以解决每个 OP 的后续问题的 CTA 子集模式

<块引用>

所以这个 <alternative test="@direction='a_value' 而 not(@another_attribute)"/> 是正确的，会正确吗?

是的，但请注意，您的 XSD 处理器可能会使用 XPath CTA(条件类型分配)默认子集.(例如，Xerces 以及大多数基于 Xerces 的工具都会执行此操作.)如果是这种情况，您将收到如下所示的错误:

<块引用>

c-cta-xpath:无法编译 XPath 表达式not(@direction)"在 CTA 评估期间，在cta-subset"模式下成功.

c-cta-xpath:XPath 表达式 '@direction='a_value' 和not(@another_attribute)' 无法在 'cta-subset' 中成功编译模式，在 CTA 评估期间.

要使用完整的 XPath 2.0 而不是 CTA 子集，请相应地配置您的工具.例如，对于 Xerces，将以下功能设置为true":

http://apache.org/xml/features/validation/cta-full-xpath-checking

在 oXygen 中，Options > 中有一个复选框.首选项XML >XML解析器XML 模式，它将为您控制功能的价值.

使用完整的 XPath 2.0，是的，您可以按照您在评论中建议的方式使用 和.

I would like to ask if someone knows how to make an XSD 1.1 Conditional Type Assignment check if an element hasn't an attribute using the XPath query, e.g.:

<!--inline alternative type definitions --> 
<element name="TimeTravel" type="TravelType"> 
      <alternative test="@direction='Future'"> 
          <complexType> 
              <complexContent> 
              <restriction base="TravelType" 
                         .... 
<!--        some past travel related elements go here --> 
            </complexType> 
       </alternative> 
      <alternative test="@direction='Past'"> 
          <complexType> 
              <complexContent> 
              <restriction base="TravelType" 
                         .... 
   <!--        some future travel related elements go here --> 
            </complexType> 
       </alternative> 
  </element> 
                          OR 
<!--Named alternative type definitions --> 
<element name="TimeTravel" type="TravelType"> 
   <alternative test="@direction='Future' type="FutureTravelType"/> 
   <alternative test="@direction='Past' type="PastTravelType"/> 
</element>

In this example the 'alternative test=""' checks whether the attribute "direction" of the TimeTravel element has a value of "Future" or "Past". How should I write the XPath query to check if e.g. there's no "direction" attribute for the current element?

解决方案

The XPath "@direction" will test for the presence of a direction attribute on the current element:

<alternative test="@direction" type="DirectionType"/>

The XPath "not(@direction)" will test for the absence of a direction attribute on the current element:

<alternative test="not(@direction)" type="NoDirectionType"/>

Note also that the alternative/@test attribute can be omitted altogether to provide a default type.

<alternative type="DefaultType"/>

Update to address CTA subset mode per OP's follow-up question

So this <alternative test="@direction='a_value' and not(@another_attribute)"/> is correct and would make it right?

Yes, but be aware that your XSD processor may use the XPath CTA (Conditional Type Assignment) subset by default. (Xerces, and therefore most Xerces-based tools, do this, for example.) If this is the case, you will get an error that looks something like this:

c-cta-xpath: The XPath expression 'not(@direction)' couldn't compile successfully in 'cta-subset' mode, during CTA evaluation.

c-cta-xpath: The XPath expression '@direction='a_value' and not(@another_attribute)' couldn't compile successfully in 'cta-subset' mode, during CTA evaluation.

To use full XPath 2.0 rather than the CTA subset, configure your tool accordingly. For example, for Xerces, set the following feature to 'true':

http://apache.org/xml/features/validation/cta-full-xpath-checking

In oXygen, there's a checkbox in Options > Preferences > XML > XML Parser > XML Schema that will control the value of the feature for you.

Using full XPath 2.0, yes, you can use and in the manner you suggest in your comment.

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