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Re: What is an RDF Query?

From: Sandro Hawke <sandro@w3.org>
Date: Tue Sep 11 09:12:15 2001
Message-Id: <200109111309.f8BD9HB03139@wadimousa.hawke.org>
To: pat hayes <phayes@ai.uwf.edu>
cc: "Eric Prud'hommeaux" <eric@w3.org>, www-rdf-rules@w3.org

> <joke> The syntax of RQF could be identical to that of N-triples 
> except that an RQF document must end with a literal of the form 
> [Canadian: ", eh?"] [US: ", right?"], etc.
> </joke>

very funny.  :-)

> The processing appropriate to RQF would be somewhat different from 
> that for RDF. In particular, anonNodes in RQF documents would have to 
> be treated as genuine variables which can be bound to values at run 
> time, as discussed in section 3. A unification process which binds an 
> RQF variable to an RDF uriref or anonNode would be a central part of 
> the machinery for linking RDF assertions to the RQF queries which 
> they entail.

I don't see anything terribly wrong with having multiple formats and
protocols (such as for assertion and query), but would you agree we
could do it all with assertions?

Instead of being able to make assertions
      "Ralph is in his office."

and make queries
      "Is Ralph is in his office?"

and maybe make weak assertions (or I dunno what-all)
      (I suspect that) "Ralph is in his office."

we could just use assertions for everything:
       "Ralph is in his office."
       "I want to know whether Ralph is in his office."
       "I suspect that Ralph is in his office."

Of course this requires a vocabulary (ontology) for expressing wanting
to know things (queries) and suspecting things (weak assertions) or
whatever.   

But as to existential variables: yes, if we can't get existential
variables in the basic assertion language, then we'll need a much more
contorted vocabulary to describe queries, and it might be better to go
with a query language as you suggest.

    -- sandro
Received on Tuesday, 11 September 2001 09:12:15 GMT

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