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Re: RDFCore WG: Datatyping documents

From: Jonathan Borden <jborden@mediaone.net>
Date: Mon, 28 Jan 2002 08:44:44 -0500
Message-ID: <066401c1a801$f22577e0$0a2e249b@nemc.org>
To: "Patrick Stickler" <patrick.stickler@nokia.com>, "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "RDF Interest" <www-rdf-interest@w3.org>
Cc: "RDF Comments" <www-rdf-comments@w3.org>, <www-xml-schema-comments@w3.org>
Patrick Stickler wrote:

> On 2002-01-27 22:12, "ext Jonathan Borden" <jborden@mediaone.net> wrote:
>
>
> >
http://lists.w3.org/Archives/Public/www-archive/2002Jan/att-0128/01-RDF_Data
> >> typing.htm
> >>
> >
> > This proposal appears to be more dependent on XML Schema datatypes and
hence
> > suffers more acutely from the probem that there is currently no defined
way
> > to assign a URI to a general XML Schema datatype (which is refered to by
its
> > QName). Same issues as above. I fear that if you simply change the names
to
> > "rdfdt:integer" and "rdfdt:string" there is not much enough here to say
what
> > these datatypes actually are (beyond the fact that we all know what an
> > 'integer' is).
>
> In order for any datatyping scheme to work with RDF, datatypes must
> have URI denotation. If XML Schema does not define URIs for datatypes
> (which I think may be debatable), then XML Schema datatypes cannot
> be used with RDF.

If this is the case, then _don't_ do it. A halfbaked attempt to shoehorn RDF
types into XML Schema types is worse than simply defining RDF types. That
said, I agree that it would be useful if RDF were able to adopt XML Schema
datatypes. But RDF needs to understand how XML Schema works (by QNames not
URIs for a start)

>
> Note that no qnames exist in the RDF graph. Qnames are a mechanism
> of the XML serialization. If XML Schema datatype qnames cannot
> be consistently and correctly maped to URIs, then that means
> that XML Schema and RDF are, at least on a practical level (though
> certainly not on an abstract level) incompatable.

That is one issue, the other is that RDF ought not trample on XML Schemas
URIs and URI prefixes. This simply creates confusion for people reading and
using the specifications.

Suppose I were to introduce a new vocabulary and distribute software that
used new names qualified by the RDF namespace, or something like the RDF
namespace, would the RDF WG be happy about that?

>
> However, one final comment, I think that it is possible to work
> with XML Schema datatype URIs with the present RDF/XML serialization
> without recourse to qnames. We do, however, tend to use qnames
> in examples for discussion as a convenience, but could also use
> only URIs.
>
> The only question remaining, then, is what are the official URIs
> for pre-defined XML Schema simple datatypes?
>

These are well defined, and if the URIs were limited to these I would have
no objection. That means (for RDF):

1) don't define new URIs (which includes namespace names!) that start with
http://www.w3.org/2001/XMLSchema

--- any such URIs need to be documented in XML Schema for _sanity sake_

2) don't bind the prefix "xsd" to other than that URI, even though it is
legal according to XML Namespaces, it just causes confusion.

-- again, this is a sanity check.

Jonathan
Received on Monday, 28 January 2002 08:47:13 UTC

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