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Re: evaluating SPARQL w.r.t an RDF query language survey (valueTesting)

From: Dan Connolly <connolly@w3.org>
Date: Tue, 12 Apr 2005 12:00:00 -0500
To: jos.deroo@agfa.com
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-Id: <1113325200.4891.172.camel@localhost>

On Thu, 2005-04-07 at 01:30 +0200, jos.deroo@agfa.com wrote:
> Dan Connolly wrote:
[...]
> > That was not a popular design when it was discussed in Helsinki
> > under issue useMentionOp
> >   http://www.w3.org/2001/sw/DataAccess/ftf4.html#itemumop
> >  <- http://www.w3.org/2001/sw/DataAccess/issues#useMentionOp
> >
> > Let's see... no, you weren't there for that one. You might
> > want to look over the record of that item and see if the
> > rationale/discussion there satisfies you. (I think I meant
> > to abstain but was too busy chairing to get my abstention
> > recorded.)
> 
> OK, I read record and would certainly have liked the discussion
> (but had other f2f's at that time) and all I can really add
> is that we use that design of "treating mathematical inferences
> like RDFS and other inferences" since 5 years it really works.
> 
> > If not, you can ask to re-open the issue.
> 
> An implementation can convert pieces of WHERE triple patterns
> into certain internal (FILTER) expressions and they could
> behave much like traditional programming language expressions
> and I think it is best to keep that for the implementation
> instead of prescibing it (just being delarative is fine).
> Also given the position below, I would ask to re-open and
> drop FILTER.

I think useMentionOp wasn't really the closest issue to
what you're talking about. I think valueTesting is closer.
valueTesting is currently open. EricP and DaveB have
an action to present a design by the 19 Apr teleconference.
I expect them to continue with the FILTER design.
I think it's reasonably mature. I was able to use it
for many of these survey examples. Jeen turned those
into tests and Andy pointed out that ARQ handles them.

I think there are a lot of details to work out in
moving things like < and = out of FILTER and into
the graph pattern... especially w.r.t. negation.
I'm not sure anybody has time to work out a complete
proposal. But I guess you have it implemented, so maybe
you can explain how the various details work?

You might try taking each of the examples from the
editor's draft and each of these query language survey
examples and writing them without FILTER.


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Tuesday, 12 April 2005 17:00:01 GMT

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