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Re: Comments on "SPARQL Query Language for RDF" (issues#SOURCE , UNSAID)

From: Dan Connolly <connolly@w3.org>
Date: Fri, 02 Sep 2005 08:23:04 -0500
To: Enrico Franconi <franconi@inf.unibz.it>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>, Sergio Tessaris <tessaris@inf.unibz.it>
Message-Id: <1125667385.16011.761.camel@dirk>

On Fri, 2005-09-02 at 04:27 +0200, Enrico Franconi wrote:
[...]
> As a first exercise, in [2] we already worked out the formal  
> semantics for core SPARQL and we also give some complexity result.
> We have a major concern on the possibility of giving any clear  
> semantics to the querying provenance part, which we probably would  
> prefer to leave out of the normative document.


This sounds like a request to re-open the SOURCE issue (and,
most likely, the UNSAID issue).
  http://www.w3.org/2001/sw/DataAccess/issues#SOURCE

I note that the relevant design objective... 

  4.2 Data Integration and Aggregation
  http://www.w3.org/TR/rdf-dawg-uc/#d4.2

was adopted over the objection of Network Inference, and that
Klyne's Apr 2005 comment says "I think these should be removed
from the basic SPARQL core ...".

Also, we have a recent last call comment

"We would like to see 
a more formal definition of queries (and their results) 
in terms of RDF semantics"
 -- Barstow/Lassila 1 Sep 2005
 http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Sep/0007.html

to which I replied...

[[
I suppose we could make explicit that for a query pattern P,
if S is a solution w.r.t. an input graph G,
then S(P) is entailed by G. Is that what you have in mind?

I think the idea can be expanded to cover UNION straightforwardly,
and perhaps OPTIONAL with some effort, but I don't know how this
applies to queries that use the GRAPH keyword.
]]
 -- http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Sep/0008.html


So there does seem to be a non-trivial amount of new information
since our 2005-01-19 decision on the SOURCE issue.

On the other hand, to re-open it adds considerable risk to our schedule.

I'll consider for a while whether or not to re-open it. Advice is welcome.


> cheers
> --e.
> 
> [1] <http://www.inf.unibz.it/krdb/w3c/sparql-notes-fub.pdf>
> [2] <http://www.inf.unibz.it/krdb/w3c/rdf-sparql-semantics.pdf>

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Friday, 2 September 2005 13:23:12 GMT

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