Re: Schema constraint

[Eric van der Vlist <vdv@dyomedea.com>]

Tony.Coates@reuters.com wrote:
> 
> On 06/07/2001 16:32:36 Phil Ruelle wrote:
> 
> >Can anyone tell me if it's possible to write a constraint with XML
> >Schema to enforce that for an element with two child elements at
> >least one of them exists? (I thought this had been asked before but
> >couldn't find it in the archives)
> 
> Have a look at the attached sample.  It's not ideal, but it works when what you need is "at least one of two".  (See attached file: at-least-one.zip)

You're right, it works when it's "two elements in any order and with 0
or 1 occurrences and at least one of them" and I have been too fast when
I have answered.

It would work also (by removing one line from your schema) if it's "two
elements with a defined order and with 0 or 1 occurrences and at least
one of them".

What wouldn't be possible (IMHO) is "two elements in any order and with
any number of occurrences and at least one of them" which had been my
interpretation of the problem! 

Eric

> 
>      Cheers,
>           Tony.
> ========
> Anthony B. Coates
> (1) Content Distribution Architect - Project Gazelle
> (2) Leader of XML Architecture & Design - Chief Technology Office
> Reuters Plc, London.
> tony.coates@reuters.com
> ========
> 
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-- 
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             http://conferences.oreillynet.com/cs/os2001/view/e_spkr/790
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Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
http://xsltunit.org      http://4xt.org           http://examplotron.org
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