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RE: requirement: rdfs query (for lack of a better name...)

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Fri, 7 May 2004 20:50:25 +0100
To: "'Pat Hayes'" <phayes@ihmc.us>
Cc: "'RDF Data Access Working Group'" <public-rdf-dawg@w3.org>
Message-ID: <000001c4346c$90dc3740$0a01a8c0@atlas>



-------- Original Message --------
> From: Pat Hayes <mailto:phayes@ihmc.us>
> Date: 07 May 2004 18:29
> 
> > -------- Original Message --------
> > >  From: public-rdf-dawg-request@w3.org <>
> > >  Date: 06 May 2004 19:06
> > > 
> > >  On Thu, May 06, 2004 at 12:52:40 -0500, Kendall Clark wrote:  >
> > >  Requirement  > ----------- > It should be possible to query the
> > >  RDFS structure of an RDF graph to > find, for example, the parents
> > >  and instances of a class or the class  > tree. >
> > >  > Discussion
> > >  > ----------
> > >  > I'm not sure whether this comes down, in the end, to a semantic
> > >  > requirement or just a request for sugar for a particular kind of
> > >  > query; but what my users need (and we have implemented in a
> > >  really > ugly, API munging way) is the ability to ask for all the
> > >  instances of > a class, all the parents of a class, and so on.
> > >  Being able to do these > queries, and being able to do them
> > >  "easily" (yes, I know, untestable, > but still...) is a real
> > > requirement for us. 
> > > 
> > >  Isn't that a question of what inference your RDFS engine supports?
> > > 
> > >  If you do RDFS then (?x <rdfs:subclassOf> ?y) will give you  all
> > > the superclasses of ?y in ?x.
> > 
> > Agreed, it does - but sometimes the application wants to find direct
> > subclass relationships
> 
> define 'direct'. (I don't think you will be able to in way that makes
> sense in an RDF context.) 
> 
> Pat

Probably not.  The usages I have seen often come from people writing
editors.  Sometimes they want to view the model with inference and sometimes
without.  They think of the graph as the same "it".  

> 
> 
> > and sometimes all the transitive entailments. e.g.
> > writing an editor. It is possible to want the both the direct
> > relationship in one part of the query pattern and yet want RDFS
> > inference elsewhere in the same query.
> > 
> > > 
> > >  - Steve
> > 
> > 	Andy
Received on Friday, 7 May 2004 15:51:45 GMT

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