xml-dev - Re: DTD design

[Marcus Carr <mrc@allette.com.au>]

heiko.grussbach@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@listserv.heanet.ie>'.


--
Regards,

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



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