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Re: Formal Semantics of OWL + RDF + SPARQL + SWRL

From: Danny Ayers <danny.ayers@gmail.com>
Date: Tue, 6 Dec 2005 10:47:59 +0100
Message-ID: <1f2ed5cd0512060147l549e9490v3eb7fabe7c3babe0@mail.gmail.com>
To: Adrian Walker <adrianw@snet.net>
Cc: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, semantic-web@w3.org

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.

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

Cheers,
Danny.

--

http://dannyayers.com
Received on Tuesday, 6 December 2005 10:41:21 GMT

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