RE: optional, but at least one required

You need to specify the requirements in a little more detail:

* are multiple occurrences of a, b, and c allowed?

* what constraints do you want to impose on the ordering of the elements?

Michael Kay
http://www.saxonica.com/
 

> -----Original Message-----
> From: xmlschema-dev-request@w3.org 
> [mailto:xmlschema-dev-request@w3.org] On Behalf Of Brian Bonner
> Sent: 04 January 2006 19:22
> To: xmlschema-dev@w3.org
> Subject: optional, but at least one required
> 
> 
> Hello,
> 
> Is there a way through restrictions or xmlschema in general to create
> the following criteria?
> 
> <options>
>      <a></a>
>      <b></b>
>      <c></c>
> </options>
> 
> where the rule is that a, b and c are all optional, but at least one
> of a, b or c is required.
> 
> Thanks.
> 
> Brian
> 
> 
>