Re: [xml-dev] having problems with the "|" in field's element inthe xs:key el ement

Please help me out here - from Schema Part 1:

"{fields} specifies XPath expressions relative to each element selected
by a {selector}. This must identify a single node (element or attribute)
whose content or value, which must be of a simple type, is used in the
constraint. It is possible to specify an ordered list of {fields}s, to
cater to multi-field keys, keyrefs, and uniqueness constraints"

ALSO

"{fields} 
A non-empty list of restricted XPath ([XPath]) expressions."

Clicking on [XPath] above yields a URL to the XPath 1.0 spec.

Please confirm what I may be missing.

Thanks,
Joe Chiusano
Booz | Allen | Hamilton

Jeff Lowery wrote:
> 
> > From: Chiusano Joseph [mailto:]
> 
> > The use of the "|" (union) operator is valid in the xs:field
> > element, as
> > the contents of this field must be a valid XPath expression
> > (and "|" is
> > a component of a valid XPath expression).
> 
> Joseph,  XPaths are restricted in XML Schema:
> 
> Path   ::=   ('.//')? ( Step '/' )* ( Step | '@' NameTest )
> 
> Step   ::=   '.' | NameTest
> 
> NameTest   ::=   QName | '*' | NCName ':' '*'
> 
> The only ORs I see here are the BNF ORs.