Re: Either-Or elements

You'll want to use the xsd:choice node. i.e.:

<xsd:complexType name="somethingType">
  <xsd:sequence minOccurs="1" maxOccurs="1">
    <xsd:choice>
      <xsd:element name="foo"/>
      <xsd:element name="bar"/>
    </xsd:choice>
  </xsd:sequence>
</xsd:complexType>

By nesting the xsd:choice within a xsd:sequence node allows you to force how many times this "choice" is allowed. From your sample schema, it seemed like you only wanted it to occur once, thus the min/max in the sequence...

HTH,

Bryce K. Nielsen
SysOnyx, Inc. (www.sysonyx.com)
Makers of xmlDraft, the Smart XSD Editor
http://www.sysonyx.com/products/xmldraft


  ----- Original Message ----- 
  From: RPearse@360commerce.com 
  To: xmlschema-dev@w3.org 
  Sent: Monday, March 21, 2005 12:02 PM
  Subject: Either-Or elements



  Using a DTD, I can specify that the something element can only have foo or bar, but not both with this: <!ELEMENT something ((foo|bar)*)> 

  In an XSD, I would have this: 

  <?xml version="1.0"?> 

  <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> 

  <xsd:element name="something" type="somethingType" /> 

  <xsd:complexType name="somethingType"> 
          <xsd:sequence> 
                  <xsd:element name="foo" minOccurs="1" maxOccurs="1" /> 
                  <xsd:element name="bar" minOccurs="1" maxOccurs="1" /> 
          </xsd:sequence> 
  </xsd:complexType> 

  How would I specify that the user has to have the foo or bar element, but not both? Currently, this XSD seems to require that you have exactly one foo and one bar in your instance document. 

  Thanks, 

  Robert