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

Re: Scope

From: Libby Miller <Libby.Miller@bristol.ac.uk>
Date: Wed, 7 Nov 2001 19:52:28 +0000 (GMT)
To: Dan Brickley <danbri@w3.org>
cc: "'www-rdf-rules@w3.org'" <www-rdf-rules@w3.org>
Message-ID: <Pine.GSO.4.21.0111071931160.1705-100000@mail.ilrt.bris.ac.uk>

ok, I know there are loads of people with their own interesting query
languages for RDF (cf SWWS query bof,  
http://ilrt.org/discovery/2001/08/rdfquery-bof/, but I would really like
to get some discussion going about query languages, so I'll start:

I've been using a simple implementation of a simple query language
called SquishQL based on Guha's RDFdb ql to try out a lot of demos to
see if we can do useful things with it.
It is pretty similar to Pat's idea of an rdf graph with a question
mark after it, but has it's own SQL-ish syntax, that's supposed to be
fairly human-readable.

It's basically a graph-matching model of a list of triples, plus some 
filters like '~' '>' '=' on the resultset. It returns a table of
bindings using JDBC APIs, as it's written in java. It has no special
schema-related syntax or optimisations, and it does not do transitive
closure. It works over lots of different databases.

Despite its simplicity, I've found you can do plenty of things with
it. I've done demos of calendar data, people data, schemas data...and so
on (see urls below). Recently I've been working with Dan Brickley on
creating a SOAP interface which uses the query format and resultset 
(which it turned out to be very amenable to), and also with Andy
Seaborne looking at the similarities between RDQL and SquishQL.


Calendar demo:

RDFWeb codepiction demo:

more demos:



On Wed, 7 Nov 2001, Dan Brickley wrote:

> Hi all
> This list (as yet not widely announced / publicised, in part due to the
> difficulty of nailing down a scope) is indeed for both RDF 'rules' and
> RDF 'query' discussions.  The distinction is perhaps more easily made in
> terms of differing communities and expectations than in terms of these
> being crisply distinguishable technologies. We will have a mix of
> backgrounds and terminology here, which is something to be aware of as you
> read posts from others. EricP suggested some ideas common terminology,
> which was a useful way of opening up initial discussion.
> One way to get started on some detail might be for people to focus on what
> they've built, prototyped etc to date in this area using RDF. Setting
> aside for now the question of 'what is RDF _query_ versus _rules_', and
> swapping some brief summaries of what tools, techniques we've used for doing things
> like asking questions of an RDF database/service or representing
> and using inference rules over RDF content. We can worry about whether to
> call it a database or a knowledgebase, a query language or a logic system
> etc etc later. First, I'd love to know what people have been building...
> Anybody want to get us started?
> danbri
> -- 
> mailto:danbri@w3.org
> http://www.w3.org/People/DanBri/
Received on Wednesday, 7 November 2001 14:55:09 UTC

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