- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Tue, 06 Dec 2005 10:26:08 -0500 (EST)
- To: danny.ayers@gmail.com
- Cc: adrianw@snet.net, semantic-web@w3.org
From: Danny Ayers <danny.ayers@gmail.com> Subject: Re: Formal Semantics of OWL + RDF + SPARQL + SWRL Date: Tue, 6 Dec 2005 10:47:59 +0100 > On 12/6/05, Adrian Walker <adrianw@snet.net> wrote: > > I suspect Peter has a different point of view that I on this, but for > what it's worth: > > > A thought about "those were not the results I expected" and SPARQL... > > > > One of the bad things about the various implementations of classical SQL is > > that they have divergent semantics -- that is, they can produce different > > results given the same query and data. > > Quite. Although the idea that a store should include inferred triples > in response to a query is appealing, I think the problems are likely > to outweigh the benefits. > > I'm sure we will continue to see plenty of RDF-only stores, so the > only way systems could operate consistently would be at that level - > i.e. the query will only be over the statements explicitly asserted. I > don't know how straightforward that is to capture formally (Peter?) > but pragmatically I'm not sure there's much choice. Well, even an RDF-only store *should* be respecting the RDF semantic, which does have some non-trivial inferences. > But this doesn't rule out the potential for stores to provide extra > query endpoints, e.g. > http://example.org/query > http://example.org/apply-class-subsumption-then-query > http://example.org/apply-rdfs-rules-then-query > http://example.org/apply-owl-rules-then-query I agree that there is the possibility of allowing stores that have different functionality. I do not believe, however, that the current vision of the Semantic Web supports a good way of providing this. > Cheers, > Danny. peter
Received on Tuesday, 6 December 2005 15:26:51 UTC