> 1) the error messages that you get when there are several
> attributes would be misleading for end users
That doesn't seem a convincing argument. Saxon says:
Validation error on line 1 column 20 of file:/c:/temp/test.xml:
Identity constraint {uniqueAtt}: the field selects more than one node (See
http://www.w3.org/TR/xmlschema-1/#cvc-identity-constraint clause 3)
Not exactly ideal for "end users", but it's no more obscure than the error
messages for many other validation errors.
> 2) W3C XML Schema processors differ in their interpretation
> of the spec on this point and this leads to interoperability issues.
That's an even less convincing argument. If a schema processor doesn't
conform to the spec, then don't use it.
Michael Kay
http://www.saxonica.com
