W3C home > Mailing lists > Public > www-rdf-interest@w3.org > January 2001

Re: Formation of RDF terms

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Sun, 28 Jan 2001 20:36:03 +0000
To: Jonathan Borden <jborden@mediaone.net>
cc: RDF Interest <www-rdf-interest@w3.org>
Message-ID: <12596.980714163@tatooine.ilrt.bris.ac.uk>
>>>Jonathan Borden said:
> Dave Beckett wrote:
> >
> > ... and this is exactly what we have been discussing.  This property
> > allows the relationship to be made without doing any delving into
> > parsing URIs - which isn't possible for general URIs.  I think RDF
> > shouldn't get into this game.
> 
> Unfortunately RDF is already in this game in RDF M&S 1.0. Every typedNode
> qname is converted into a URI which is the subject of the rdf:type.
> ...

No.  The XML syntax in the RDF M&S document constructs URIs from XML
namespace prefix URIs and XML element names (qnames).  It never takes
URIs and de-constructs them - which is what I was saying.  You cannot
take an arbitrary URI and deconstruct it to a namespace and a qname
(in RDF).

In the RDF formal model (section 5) this is even more important since
there are no XML syntax concepts at all.  URIs are 'black boxes' that
are never broken open.

> ... As we
> know this is fine for 'RDF aware' namespaces but broken for namespaces which
> end in a letter or number e.g. http://www.w3.org/2000/10/XMLSchema, this
> acute problem this causes is the definition of XSD datatypes e.g.:
> 
> <xsd:unsignedInt rdf:about="http://www.foo.org/someNumber/123">
> 	...
> </xsd:unsignedInt>
> 
> Ought RDF applications use XML Schema datatypes?

The RDF M&S Recommendation date was February 1999.  The XML schema
series are still candidate recommendations dated late 2000 and are
thus several years later.  Thus the RDF M&S document couldn't really
depend on XML schema!   [ However in a revised document ... ]

Maybe there should be a note on pros/cons of namespaces that intend
to be used with RDF to avoid some of the things you mention
(e.g. dealing with if the namespaces should end in # or /)

> What triples ought be generated? Certainly not:
> http://www.w3.org/2000/10/XMLSchemaunsignedInt
> 
> N3 already appends a '#' to such namespaces in a bind.

Lets leave N3 out of this and deal with the XML syntax in the
standard rather than experiments for more friendly syntax.

Dave
Received on Sunday, 28 January 2001 15:36:08 GMT

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