• From: George Cristian Bina <george@o...>
• To: Andrew Welch <andrew.j.welch@g...>
• Date: Thu, 14 Aug 2008 17:01:03 +0300

That's nice, but there's no need to involve substitution groups to get 
the same result:

     <complexType name="ThreeElements">
         <choice maxOccurs="unbounded">
             <element name="A" type="string"/>
             <element name="B" type="string"/>
             <element name="C" type="string"/>
         </choice>
     </complexType>

But I believe Roger does not want to allow multiple occurrences of the 
same element while the above allows that.

Best Regards,
George
-- 
George Cristian Bina
<oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
http://www.oxygenxml.com

Andrew Welch wrote:
>> Consider this problem: you have 3 elements - A, B, C - and you need at
>> least one of them to be present in your XML instance document.
> 
> How about:
> 
>     <xs:element name="baseType"/>
> 
>     <xs:element name="A" substitutionGroup="baseType"/>
>     <xs:element name="B" substitutionGroup="baseType"/>
>     <xs:element name="C" substitutionGroup="baseType"/>
> 
>     <xs:complexType name="whatever">
>         <xs:sequence>
>             <xs:element ref="baseType" maxOccurs="unbounded"/>
>         </xs:sequence>
>     </xs:complexType>
> 
> ?
> 

• References:
  • XML Schema quiz: 3 elements and at least one must be present
    • From: "Costello, Roger L." <costello@m...>
  • Re: XML Schema quiz: 3 elements and at least one must be present
    • From: "Andrew Welch" <andrew.j.welch@g...>