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"Chiusano Joseph" <chiusano_joseph@bah.com> writes:
> 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.
You're not missing anything -- Jeff missed one production, namely:
[Field] ::= Path ( '|' Path )*
> Jeff Lowery wrote:
> >
> > > From: Chiusano Joseph [mailto:chiusano_joseph@bah.com]
> >
> > > 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.
--
Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
Half-time member of W3C Team
2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]
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