DTD design

Marcus Carr mrc at allette.com.au
Wed Dec 22 23:13:22 GMT 1999

heiko.grussbach at crpht.lu wrote:

> I have the following problem, I want to define an element E that may
> contain elements A,B,C. Order should be insignificant and A,B and C are all
> optional. Furthermore, A,B and C may each be replaced by X.

If more elements were to be added as children of E, the exponential combinations would make maintenance of content models untenable - it's
reasonable then to conclude that this is not an appropriate approach from the outset. I would use something like:

<!ELEMENT E   (A | B | C | X)*>

and use a schema or XSL to advise when elements are found to behave in a way contrary to your intentions but not expressed by the content model.

BTW, this question is probably more suited to 'General discussion of Extensible Markup Language <XML-L at listserv.heanet.ie>'.


Marcus Carr                      email:  mrc at allette.com.au
Allette Systems (Australia)      www:    http://www.allette.com.au
"Everything should be made as simple as possible, but not simpler."
       - Einstein

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at ic.ac.uk
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1
To unsubscribe, mailto:majordomo at ic.ac.uk the following message;
unsubscribe xml-dev
To subscribe to the digests, mailto:majordomo at ic.ac.uk the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa at ic.ac.uk)

More information about the Xml-dev mailing list