XML Schema with a combination of choice and all

Question

I want to do the validations like:

<A>
   <B> or <C>
   <D>
</A>

In the , the first element should be one of the B and C. The second element is D. And at the same time, the first element B or C and the second element do not in sequence. It could become and . Anybody know how to do it?

Answer 1

I get the best practice. It should be as below:

<xs:element name="A">
   <xs:complexType>
      <xs:all>
        <xs:element ref="Choice" minOccurs="1" maxOccurs="1"/>
        <xs:element ref="D" minOccurs="0" maxOccurs="1"/>
      </xs:all>
   </xs:complexType>
 </xs:element>

 <xs:element name="D" type="xs:string"/>

 <xs:element name="Choice" abstract="true"/> 

 <xs:element name="B" substitutionGroup="Choice"> 
 </xs:element>

 <xs:element name="C" substitutionGroup="Choice"> 
 </xs:element>