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Re: Restrictions on existence of attributes?

• To: "xml-dev@l..." <xml-dev@l...>
• Subject: Re: Restrictions on existence of attributes?
• From: Eric van der Vlist <vdv@d...>
• Date: Tue, 27 Jun 2006 13:15:05 +0200
• In-reply-to: <CPEELKNOKCDGNPIPEIAFEEPKEIAA.hbartel@c...>
• Organization: Dyomedea (http://dyomedea.com)
• References: <CPEELKNOKCDGNPIPEIAFEEPKEIAA.hbartel@c...>

Le lundi 26 juin 2006 à 17:09 -0700, Howard Bartel a écrit :
> How do I specify that an element MUST have ONLY ONE of a set of possible
> attributes?

Use either RELAX NG instead of W3C ML Schema:

element foo {
  attribute bar {text}|
  attribute bat {text}|
  attribute baz {text}
}

Or Schematron in addition to W3C XML Schema:

<xs:element name="foo">
  <xs:complexType>
  ...
  <xs:complexType>
  <xs:annotation
    <xs:appinfo>
     <sch:rule context="foo">
      <assert test="count(@bar|@bat|@baz)=1">
        there should be only one of @bar, @bat and @baz.
     </assert>
   </xs:appinfo>
 </xs:annotation>
</xs:element>

> I understand that there is a "choice" option but it seems that this only
> applies to elements, not attributes within an element.

Exactly.

Eric

-- 
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Weblog:
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------------------------------------------------------------------------
Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
(ISO) RELAX NG   ISBN:0-596-00421-4 http://oreilly.com/catalog/relax
(W3C) XML Schema ISBN:0-596-00252-1 http://oreilly.com/catalog/xmlschema
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    • From: "Howard Bartel" <hbartel@c...>

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