- From: Pat Hayes <phayes@ihmc.us>
- Date: Fri, 7 May 2004 12:28:47 -0500
- To: "Seaborne, Andy" <andy.seaborne@hp.com>
- Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
>-------- 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 >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 -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Friday, 7 May 2004 13:28:49 UTC