Is there a way to allow 'this' attribute or 'this other' attribute, but not both?

Question

I am trying to allow for two attribute values for one element. This is how I have it done now, but I only want to allow 1 of the 2, but not both.

<contact phoneH="cell">8025550000</contact>
<contact phoneW="work"> 8025550094</contact>

I am looking to be able to do something like this:

<xsd:attribute name="phoneH|phoneW" type="xsd:string" />

Is there a way to do use the restriction element with attributes?

Thanks,
Levi

Answer 1

I don't believe that attribute constraint is possible with XML Schema.

You can apply additional validation mechanisms (i.e. schematron) or use a different schema implementation (i.e. Relax-NG)

http://lists.xml.org/archives/xml-dev/200107/msg00070.html

Unfortunately you can't do this with W3C XML Schema. As I see it you have two options:

1) Change to a different schema dialect (I think RELAX-NG support this functionality) 2) Express you co-constraint using an embedded schematron rule

These constraints can be validated with the new Schematron Validator from Topologi. The tool is free and can be downloaded from www.topologi.com.

Answer 2

You can't do this with W3C xsd.

An alternative would be making phoneH and phoneW subelements of contact, and using xs:choice to limit the user to one or the other subelement.