W3C home > Mailing lists > Public > www-rdf-rules@w3.org > September 2001

Re: What is an RDF Query?

From: Sandro Hawke <sandro@w3.org>
Date: Tue Sep 11 14:45:31 2001
Message-Id: <200109111843.f8BIhoR04716@wadimousa.hawke.org>
To: pat hayes <phayes@ai.uwf.edu>
cc: www-rdf-rules@w3.org

> >we could just use assertions for everything:
> >       "Ralph is in his office."
> >       "I want to know whether Ralph is in his office."
> The trouble with this is that it invites the response: "So? Why 
> should I care what you want?"  which would be impolite in human 
> discourse, of course, but only because humans have a mutually agreed 
> set of social conventions about being helpful to one another, etc. . 
> Without some such conventions, nothing particular follows from your 
> needing something.

Perhaps I should have phrased it a little better, as
     "Tell me whether Ralph is in his office."

which puts us where we are with current client/server systems, which
pretty-much do their best to follow any instructions they receive
(pending some authorization procedures we could discuss).

I'd love to go a bit farther, to things like

     "If you tell me whether Ralph is in his office within the
     next 3 seconds, and your information turns out to be correct,
     I'll transfer $0.10 to an account of your chosing."

but that's probably more researchy than we should be talking about
right now.

> What we really need here is a set of agreed protocols for asking, 
> asserting, querying, whatever, which are related in systematic ways 
> to the contents of what are asserted, queried, etc.

Sure.  The question I think we're debating in this thread is simply
whether those protocols should use an RDF syntax at the bottom-layer
or not.  We could define a query protocol with an S-Expression syntax,
an ASN.1 syntax, a internet "simple" (a la SMTP) style syntax, etc.  I
suggest we ignore the syntax and simply say we're using an RDF
assertional graph (knowledge base) to convey the query (and its response).

Someone else (us on another mailing list, perhaps) can decide how the
RDF assertions get securely passed from one agent to another.  Here,
we can just talk about what kind of RDF statements "Agent A" would
make to "Agent B" to get "Agent B" to do some useful query work and
send some results back to "Agent A".

> >But as to existential variables: yes, if we can't get existential
> >variables in the basic assertion language,
> Well, RDF has them, so relax :-)

Thank you.   <big><sigh of relief /> :-) </big> 

    -- sandro
Received on Tuesday, 11 September 2001 14:45:31 UTC

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