- 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>
-------- 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 UTC