XML Tutorial/XML Schema/ID

The ID datatype is derived from the NCName type.

<!-- schema -->
<xsd:element name="bank">
  <xsd:complexType>
   <xsd:complexContent>
    <xsd:extension base="xsd:anyType">
    <xsd:attribute name="degree" type="xsd:ID"/>
    </xsd:extension>
   </xsd:complexContent>
  </xsd:complexType>
</xsd:element>
<!-- instance document -->
<bank branch="412x">Northern</bank>