Restrict attribute values in XML schema

Question

Is it possible to restrict a combination of attribute values in XML schema? I have a tag with two attributes and I would like to permit some combinations of their values. Eg if attribute_1 has value "A", then attribute_2 must not have value "B".

Answer 1

In XSD 1.1 you can use assertions . Something like (untested):

<xs:element name="SomeType">
  <xs:complexType>
    <xs:attribute name="attribute_1" type="xs:string">
    <xs:attribute name="attribute_2" type="xs:string"/>
    <xs:assert test="if (@attribute_1 = 'A') then @attribute_2 != 'B' else true()"/>
  </xs:complexType>
</xs:element>

See more examples here .