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Re: SeRQL an RDF rule language: scoping Rules vs Query in W3C work

From: jo walsh <jo@abduction.org>
Date: Tue, 4 Nov 2003 19:10:57 +0000 (GMT)
To: www-rdf-rules@w3.org
Message-ID: <Pine.BSF.3.96.1031104141632.92752F-100000@ebe.abduction.org>


hi dan, list,

> > In terms of possible new technology areas, 'Rules' and 'Query' 
> > are two topics for recommendation-track work.

> It would be hard to envisage a usable (expressive enough) RDF query
> language that does not at least partially intrude on rules
> territory: after all, a query is generally speaking just a rule
> without a head.

this cuts the question to the core for me; this looks like prolog
statements that are ground or not - in the query there are variables, the 
rules are ground. it makes a lot of sense that one language be capable of
expressing both, never got that before now.

i was and still am boggled by this article of kendall clark's discussing a
plethora of OWL rules systems and meta-markup:
http://www.xml.com/pub/a/2003/10/23/iswc.html

the other day we dreamed up a query language[0] that extends and
simplifies squishQL but the decisions would apply to a rules language:

- it is not RDF/XML or at least has a primary alternative
- the aim is for it 'to read like a language i already know'
- it doesn't have to perform variable substitution, you can ask for a
whole graph    
- it extends to making asssertions and retractions

here's an interesting pile of old use cases:
http://rdfstore.sourceforge.net/2002/06/24/rdf-query/   

here's a survey, though it looks a little empty:   
http://www.w3.org/2001/11/13-RDF-Query-Rules/ 

is it worth looking at 'common logic'?
http://cl.tamu.edu/docs/cl/cl-latest.html is beyond my immediate
understanding. is the overlap with OWL considerable here?  

i would enjoy a process of collecting design decisions about QLs that are 
proliferating. e.g. a query returning a whole graph is something i need
for an rdf/xml http based interface one can post queries and assertions
to, but dajobe mentioned he thought most people didn't want that.
 
> My gut reaction is that although the technologies are very similar,
> the use cases are different. This may reflect on requirements for
> ease of use, expressiveness and syntax.

a QL-lite situation ;) i'd happily help contrib use cases from
applications to such a process. i'd like to potentially see layers of
subsets or 'natural language' equivalents to simple statements being
layered over the top of a language that spans both rules and query; i
would find such a thing unspeakably useful.


jo
xx
[0] http://iconocla.st/hacks/query/ul1.bnf
--
"Common sense won't tell you. We have to tell each other." -DNA
Received on Tuesday, 4 November 2003 14:10:58 UTC

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