[xquery-talk] Schema in xquery
geert.josten at dayon.nl
Tue Mar 6 03:41:28 PST 2012
Could one not say that 'schema' languages that have less expressiveness,
are easier to apply? Provided there are no ambiguities. I mean if a schema
language doesn't for instance support nullability, that a particular
element/attrib simply isn't allowed to be null, right?
> -----Oorspronkelijk bericht-----
> Van: talk-bounces at x-query.com [mailto:talk-bounces at x-query.com] Namens
> Michael Kay
> Verzonden: dinsdag 6 maart 2012 9:41
> Aan: talk at x-query.com
> Onderwerp: Re: [xquery-talk] Schema in xquery
> On 06/03/2012 02:27, David Lee wrote:
> > I've been contemplating the relationship between schema and type in
> aware xquery.
> > Is xquery strictly tied to XSD? That is, could an implementation
> another schema format such as rng to provide for the type system?
> It would be possible to support a different schema language, but not
> without difficulty.
> (a) XSD is the only schema language I know of that defines how elements
> and attributes in the instance document are associated with types, and
> that includes constraints (such as the notorious UPA) to make this
> association unambiguous.
> (b) Many of the concepts of XSD, such as the distinction between simple
> and complex types, substitution groups, and nullability, turn up in the
> semantics of XQuery, and would need to be mapped to the concepts of a
> different schema language.
> Michael Kay
> talk at x-query.com
More information about the talk