Schema之key、keyref

  <xs:element name="Area" type="AreaType">    <xs:key name="NameKey">      <xs:selector xpath=".                   |.//Area                   |.//Part"/>      <xs:field xpath="@Name"/>    </xs:key>    <xs:key name="PropertyNameKey">      <xs:selector xpath="./Property-List/Property"/>      <xs:field xpath="@Name"/>    </xs:key>  </xs:element>

上面的name名为NameKey的xs:key表示Area节点和Area节点下的所有Area和Part的Name属性都不允许相同name名为PropertyNameKey表示Area下Property-List下的所有Property的Name属性都是唯一的keykeyrefXpath最后列举几个Xpath的用法

/AAA
选择根元素AAA
<AAA>           <BBB/>           <CCC/>           <BBB/>           <BBB/>           <DDD>                <BBB/>           </DDD>           <CCC/>      </AAA>

/AAA/DDD/BBB
选择AAA的子元素DDD的所有子元素
<AAA>           <BBB/>           <CCC/>           <BBB/>           <BBB/>           <DDD>                <BBB/>           </DDD>           <CCC/>      </AAA>
在XLab中打开实例 | 树视图(JPG)

//BBB
选择所有BBB元素
<AAA>           <BBB/>           <CCC/>           <BBB/>           <DDD>                <BBB/>           </DDD>           <CCC>                <DDD>                     <BBB/>                     <BBB/>                </DDD>           </CCC>      </AAA>