XML schema for elements with same name but different sub elements

Question

What I'm looking to be able to create is one XSD which would validate both of the following:

<parent>
 <mother>
  <name>
   <firstname>foo</firstname>
   <surname> bar </surname>
   <maidenname>rab</maidenname>
  </name>
 </mother>
</parent>

and

<parent>
 <father>
  <name>
   <firstname>foo</firstname>
   <surname> bar </surname>
  </name>
 </father>
</parent>

I ideally want to be able to use the same element name but have different requirements for it based on the parent attribute. What I've tried so far is:

    <?xml version="1.0" encoding="UTF-8" ?>

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"&gt;
  <xs:element name="firstname">
    <xs:complexType mixed="true" />
  </xs:element>

  <xs:element name="maidenname">
    <xs:complexType mixed="true" />
  </xs:element>

  <xs:element name="mother">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="name" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="father">
    <xs:complexType>
      <xs:sequence>
        <xs:element ref="name" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="name">
    <xs:complexType>
      <xs:all>
        <xs:element ref="firstname" />
        <xs:element ref="surname" />
        <xs:element ref="maidenname" />
      </xs:all>
    </xs:complexType>
  </xs:element>

  <xs:element name="parent">
    <xs:complexType>
    <xs:choice>                                
        <xs:element ref="mother"/>
        <xs:element ref="father"/>
    </xs:choice>
    </xs:complexType>
  </xs:element>

  <xs:element name="surname">
    <xs:complexType mixed="true" />
  </xs:element>

</xs:schema>

Answer 1

You can create two different types (e.g. fathersName and mothersName) and use them for the respective name elements. Here's the full XSD:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"&gt;
  <xs:element name="firstname">
    <xs:complexType mixed="true" />
  </xs:element>

  <xs:element name="maidenname">
    <xs:complexType mixed="true" />
  </xs:element>

  <xs:element name="mother">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="name" type="mothersName" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="father">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="name" type="fathersName" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:complexType name="fathersName">
    <xs:all>
      <xs:element ref="firstname" />
      <xs:element ref="surname" />
    </xs:all>
  </xs:complexType>

  <xs:complexType name="mothersName">
    <xs:all>
      <xs:element ref="firstname" />
      <xs:element ref="surname" />
      <xs:element ref="maidenname" />
    </xs:all>
  </xs:complexType>

  <xs:element name="parent">
    <xs:complexType>
      <xs:choice>
        <xs:element ref="mother"/>
        <xs:element ref="father"/>
      </xs:choice>
    </xs:complexType>
  </xs:element>

  <xs:element name="surname">
    <xs:complexType mixed="true" />
  </xs:element>

</xs:schema>

Also, if the names are supposed to be simple strings, you could write the XSD in a more concise way:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"&gt;
  <xs:element name="mother">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="name" type="mothersName" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:element name="father">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="name" type="fathersName" />
      </xs:sequence>
    </xs:complexType>
  </xs:element>

  <xs:complexType name="fathersName">
    <xs:all>
      <xs:element name="firstname" type="xs:string" />
      <xs:element name="surname" type="xs:string" />
    </xs:all>
  </xs:complexType>

  <xs:complexType name="mothersName">
    <xs:all>
      <xs:element name="firstname" type="xs:string" />
      <xs:element name="surname" type="xs:string" />
      <xs:element name="maidenname" type="xs:string" />
    </xs:all>
  </xs:complexType>

  <xs:element name="parent">
    <xs:complexType>
      <xs:choice maxOccurs="unbounded">
        <xs:element ref="mother"/>
        <xs:element ref="father"/>
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>

Finally, you may write mothersName as an extension of fathersName, but this comes with a cost: the order of elements has to be (at least partially) fixed. Here's how the two type definitions would look:

  <!-- ... -->

  <xs:complexType name="fathersName">
    <xs:sequence>
      <xs:element name="firstname" type="xs:string" />
      <xs:element name="surname" type="xs:string" />
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="mothersName">
    <xs:complexContent>
      <xs:extension base="fathersName">
        <xs:sequence>
          <xs:element name="maidenname" type="xs:string" />
        </xs:sequence>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>

  <!-- ... -->