Re: conditional schemas

Re: conditional schemas----- Original Message ----- 
  From: Erik Beijnoff 
  To: 'Eddie Robertsson' 
  Cc: lieve.laporte@uz.kuleuven.ac.be ; xmlschema-dev@w3.org 
  Sent: Wednesday, November 28, 2001 1:53 PM
  Subject: Re: conditional schemas


  >> <actions name="access"> 
  >>     ... 
  >>     ==> the document has to contain tag <tag> 
  >>     ... 
  >> </actions> 
  >> 
  >> <actions name="settings"> 
  >>     ... 
  >>     ==> the document may not contain tag <tag> 
  >>     ... 
  >> </actions> 
  >> 
  >> In this case, can I express in the schema that if the value 
  >of name is 
  >> access, the <tag> should be present, and if the value of 
  >name is settings, 
  >> it shouldn't? 
  > 
  >Unfortunately you can't do this with W3C XML Schema. RELAX-NG 
  >can do this and 
  >the other alternative is to use W3C XML Schema with embedded 
  >Schematron rules. 
  >See my previous post [1] for an example of how to use embedded 
  >Schematron rules. 
  > 

  Wouldn't it be possible to express this with something on the form: 

  <xs:element name="testelement"> 
    <xs:complexType> 
      <xs:choice> 

        <xs:element name="actions"> 
          <xs:complexType> 
            <xs:sequence> 
              <xs:element name="tag"/> 
            </xs:sequence> 
              <xs:attribute name="name" use="required" fixed="access"/> 
          </xs:complexType> 
        </xs:element> 

        <xs:element name="actions"> 
          <xs:complexType> 
            <xs:attribute name="name" use="required" fixed="settings"/> 
          </xs:complexType> 
        </xs:element> 

      </xs:choice> 
    </xs:complexType> 
  </xs:element> 

  This is, of curse only valid under the condition that attribute "name" only can have the values "access" ot "settings". And if you feel uncomfortable with defining actions twice, make  the element declaration references two global elements, which extends a common "actions" base type.

  Best regards 
    
  Erik Beijnoff 
  Systems development 

  erik.beijnoff@addsystems.com 
  erik@beijnoff.com 



  In this case, wouldn't I have to duplicate everything that is inside the "actions" element? 'Cause that's quite a lot...

  Regards, Lieve