type

<xsd:attribute name="type" use="optional">
  <xsd:simpleType>
    <xsd:restriction base="dtSTRING">
      <xsd:maxLength value="20"/>
      <xsd:minLength value="1"/>
      <xsd:enumeration value="flat"/>
      <xsd:enumeration value="hierarchy"/>
    </xsd:restriction>
  </xsd:simpleType>
</xsd:attribute>