A RELAX schema for songs

<?xml version="1.0?>
<module
      moduleVersion="1.2"
      relaxCoreVersion="1.0"
      targetNamespace=""
      xmlns="http://www.xml.gr.jp/xmlns/relaxCore">

  <!-- Elements allowed as document roots -->
  <interface>
    <export label="SONG"/>
  </interface>

  <elementRule role="SONG">
    <sequence>
      <ref label="TITLE"/>
      <ref label="COMPOSER" occurs="*"/>
      <ref label="PRODUCER" occurs="*"/>
      <ref label="PUBLISHER" occurs="?"/>
      <ref label="YEAR"/>
      <ref label="ARTIST" occurs="+"/>
      <ref label="PRICE"  occurs="?"/>
    </sequence>
  </elementRule>
  
  <elementRule role="TITLE"     type="string"/>
  <elementRule role="COMPOSER"  type="string"/>
  <elementRule role="PRODUCER"  type="string"/>
  <elementRule role="PUBLISHER" type="string"/>
  <elementRule role="YEAR"      type="year"/>
  <elementRule role="ARTIST"    type="string"/>
  <elementRule role="PRICE"     type="string"/>

</module>