取决于属性/元素值的不同子元素 [英] Different sub-elements depending on attribute/element value
问题描述
另一个XSD问题-如何实现以下XML元素均有效:
Another XSD question - how can I achieve that the following XML elements are both valid:
<some-element>
<type>1</type>
<a>...</a>
</some-element>
<some-element>
<type>2</type>
<b>...</b>
</some-element>
子元素( <a>
或 <b>
)应取决于<type>
的内容(也可以是属性).这在RelaxNG中是如此简单-但是RelaxNG不支持密钥完整性:(
The sub-elements (either <a>
or <b>
) should depend on the content of <type>
(could also be an attribute). It would be so simple in RelaxNG - but RelaxNG doesn't support key integrity :(
有没有一种方法可以在XSD中实现呢?
Is there a way to implement this in XSD?
注意:XML模式版本1.1支持<xs:alternative>
,这可能是一个解决方案,但是afaik还没有引用实现(例如libxml2)支持此功能.因此,我正在寻找解决方法.我想出的唯一方法是:
Note: XML schema version 1.1 supports <xs:alternative>
, which might be a solution, but afaik no reference implementation (e.g. libxml2) supports this yet. So I'm searching for workarounds. The only way I've come up with is:
<type>1</type>
<some-element type="1">
<!-- simple <xs:choice> between <a> and <b> goes here -->
<a>...</a>
</some-element>
<!-- and now create a keyref between <type> and @type -->
推荐答案
最好的解决方案是删除<type/>
元素,并且对于<a/>
和<b/>
仅具有xs:choice
,并让应用程序使用xml整理类型.
The best solution is to remove the <type/>
element and only have a xs:choice
for <a/>
and <b/>
and let the application consuming the xml sort out the type.
另一种解决方案可能是让<a/>
和<b/>
的xs:choice
使用xslt脚本来验证与<a/>
和<b/>
相关的<type/>
元素.
Another solution might be to have a xs:choice
for <a/>
and <b/>
use an xslt script to do a validation of the <type/>
element in relation to <a/>
and <b/>
.
首先针对xmlschema验证xml,然后使用xslt对其进行转换,如果转换的结果为空字符串,则为有效,否则将结果字符串显示为错误消息.
First validate the xml against the xmlschema then use the xslt to do a transformation on it, if the result of the transform is empty string it is valid otherwise show the resulting string as an error message.
类似这样的事情...
Something like this...
XmlSchema:
<xs:element name="some-element">
<xs:complexType>
<xs:sequence>
<xs:element name="type" type="xs:integer" />
<xs:choice>
<xs:element name="a" type="xs:string" />
<xs:element name="b" type="xs:string" />
</xs:choice>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
Xslt:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:demo="uri:demo:namespace">
<xsl:output method="text" />
<xsl:template match="/demo:some-element">
<xsl:if test="type = 1 and not(demo:a)">
When type equals 1 element a is requred.
</xsl:if>
<xsl:if test="type = 2 and not(demo:b)">
When type equals 2 element b is requred.
</xsl:if>
</xsl:template>
</xsl:stylesheet>
这篇关于取决于属性/元素值的不同子元素的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!