RE: Restricting attribute content to not include a specific string

> Thank you very much for all your helpfull input.
> Maybe that would be a nice feature for XML Schema 1.1 to 
> allow this kind of "intersect" or "except" statements.

Now that XPath handles all schema-defined types, the obvious answer to this
and many other similar requirements is a facet

<xs:satisfies test="not(. eq 'unknown')"/>

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