Enforcing IDs in XML Schema

Hi,

I would like to use XML Schema to enforce something like the following:

<definition id="12345">
 ...
</definition>

<use_definitions>
  <def ref="12345"/>
  ...
</use_definitions>


So, if an ID is used as a reference in the <def> element, there HAS TO
BE a correpsonding <definition> element with the same ID. Is it possible
to do this in XML Schema? Ideas?

Thanks.

--
Simon

________________________________________________________________________
This email and any files transmitted with it are intended solely for the use of the individual or entity to whom they are addressed. They may contain sensitive and/or in confidence information that is covered by legal, professional or other privilege. No mistake in transmission is intended to waive or compromise any such privilege. If you have received this email in error please notify the sender at once.

This email has been scanned for viruses on behalf of STASYS Limited by
the MessageLabs Email Security System.
________________________________________________________________________

Received on Friday, 30 April 2004 06:04:34 UTC