请教XML与模式的问题

xml.xml文件内容:

<?xml version="1.0"?>
<bookstore xmlns="x-schema:xmlschema.xdr">
  <book>
      <title>i am stuent </title>
      <author>
        <fristname>j </fristname>
        <lastname>smith </lastname>
      </author>
      <price>25 </price>
  </book>
</bookstore>


xmlschema.xdr文件内容
<?xml version="1.0"?>
<schema xmlns="urn:schemas-microsoft-com:xml-data" xmlns:dt="urn:schemas-microsoft-com:xml-datatype">
  <elementtype name="firstname" content="textonly"/>
  <elementtype name="lastname" content="textonly/>
  <elementtype name="author content="eltonly">
      <element type="firstname"/>
      <element type="lastname"/>
  </elementtype>
  <elementtype name="title" content="textonly" />
  <elementtype name="price" content="textonly" dt:type="float"/>