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RE: notes from our working meeting today on query and rules stuff

From: Seaborne, Andy <Andy_Seaborne@hplb.hpl.hp.com>
Date: Wed, 19 Mar 2003 13:52:32 -0000
Message-ID: <5E13A1874524D411A876006008CD059F061D6C83@0-mail-1.hpl.hp.com>
To: "'Eric Prud'hommeaux'" <eric@w3.org>, "'Benjamin Grosof'" <bgrosof@MIT.EDU>
Cc: "'www-rdf-rules@w3.org'" <www-rdf-rules@w3.org>


One additional classification that might help, especially with an eye to any
future group work under the SW activity (WG, task force, whatever), would be
an axis of "status" including issues like is this a design, part of some
system, a widely used language.  There is going to be a pipeline from
experimental to mainstream and knowing where approximately in this pipeline
various sureyed items are would be helpful.  This not only applies to
individual systems but also to facets you are identifying - are certain
features wide spread or mainly in one system?


The abstract says """This document is intended to provide an understanding
of the concepts and issues related to querying semantic web data.""" but you
seem to be extending to rule systems.  Will there be examples of rule
systems?  This would be good.  As it broadens the area somewhat, how about
keeping a focused query section as well as a general rule system survey.


It would be good if there were and RDF vocabulary for the abstract syntax.
An XML form is OK but RDF would be better.

As to [2] - the result set vocabulary is focused on recording bound
variables although it applies to rules as well, both forward chaining (it is
just a special result template) and backward chaining where Jos [B] has
looked at the relationship to proof traces.


One way of thinking about query systems that I have found useful is the 3
facets of "location", "extraction" and "presentation".  Location is about
how a language finds nodes/arcs in the graph, Extraction is about what it
does when it has fixed on some information (e.g. extract a subgraph based on
following bNodes - you don't have an example of one of this but [A] is one
such).  Presentation is about how the results are returned - see [2]


There is a othogonal survey at [C]: instead of a single example in all the
langauges, it is examples submitted by people, with matching approaches.
All the work for this was by Alberto.


In particular, I note parallel taxonomy
development by Andy Seaborne [2]. We should try to synch up at some
point; soon? or after poking around in the space for a bit?

Now would be as good a time as any.  What had you in mind?  Are you thinking
of a vocaulary for expressing RDF queries modelled after your abstract
syntax section?


[A] http://www.hpl.hp.com/semweb/publications.htm#RDF-QBE
[B] http://lists.w3.org/Archives/Public/www-rdf-rules/2003Feb/0003.html
[C] http://rdfstore.sourceforge.net/2002/06/24/rdf-query/

[1] http://www.w3.org/2001/11/13-RDF-Query-Rules/
[2] http://www.w3.org/2003/03/rdfqr-tests/recording-query-results.html
Received on Wednesday, 19 March 2003 08:53:01 UTC

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