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Fw: SPARQL Query Language for RDF Is a Candidate Recommendation (Call for Implementations)

From: Lee Feigenbaum <feigenbl@us.ibm.com>
Date: Thu, 14 Jun 2007 17:06:03 -0400
To: public-rdf-dawg@w3.org
Message-ID: <OFE80F278C.DA03D5ED-ON852572FA.0073D3DD-852572FA.0073E95E@us.ibm.com>
Congratulations, everyone, and many thanks to Andy and Eric for your hard 
work getting us back to CR.

Onwards with testing, implementation reports, and perhaps some sort of 
terminus for our little adventure.

Lee

----- Forwarded by Lee Feigenbaum/Cambridge/IBM on 06/14/2007 05:05 PM 
-----

Susan Lesch <lesch@w3.org> 
Sent by: chairs-request@w3.org
06/14/2007 04:58 PM

To
w3c-ac-members@w3.org
cc
w3c-semweb-cg@w3.org, Jeen Broekstra <jeen@aduna.biz>, "Eric 
Prud'hommeaux" <eric@w3.org>, Lee Feigenbaum/Cambridge/IBM@IBMUS, 
Seaborne@w3.org, Andy <andy.seaborne@hp.com>, chairs@w3.org, Ivan Herman 
<ivan@w3.org>
Subject
SPARQL Query Language for RDF Is a Candidate Recommendation (Call  for 
Implementations)






Dear Advisory Committee Representative,

I am pleased to announce that SPARQL Query Language for RDF is a W3C
Candidate Recommendation. The approval and publication is in response
to the following transition request:
  http://lists.w3.org/Archives/Member/chairs/2007AprJun/0077

The disposition of Last Call comments is available:
  http://www.w3.org/2001/sw/DataAccess/lc-status-report


Formal Objections
=================
The Candidate Recommendation transition records the current status of
the six formal objections:
  http://www.w3.org/2001/sw/DataAccess/crq350

Since the last Candidate Recommendation transition, Steve Harris has
removed his objection over the resolution of fromUnionQuery, Pat Hayes
has withdrawn his objection to the resolution of rdfSemantics. Peter
F. Patel-Schneider has objected to the lack of inference in graph and
value matching, and Bob MacGregor has objected to the algebraic style
of definitions and the inclusion of a mechanism to test for unbound
variables.


Objections 1, 2 and 3
  http://www.w3.org/2001/sw/DataAccess/crq350#notXQuery
  http://www.w3.org/2001/sw/DataAccess/crq350#optional
  http://www.w3.org/2001/sw/DataAccess/crq350#aggregation
were posted by Network Inference/Cerebra, which has since been acquired
by another company who have not commented on SPARQL. These objections
were raised by a former Working Group participant and discussed in
detail at the time they were raised. The design favored by the
commenter was not acceptable to the rest of the Working Group.


In objection 4, Elliotte Harold objects to parallel syntax for
designating variables.
  http://www.w3.org/2001/sw/DataAccess/crq350#variableSyntax
It seems worthwhile to call for implementations despite this formal
objection.


Peter F. Patel-Schneider objects to the lack of inference required of
SPARQL services (objection 5):
  http://www.w3.org/2001/sw/DataAccess/crq350#matchingInference

Specifically, he would like further inference to eliminate mutually
entailed (redundant) subgraphs prior to graph matching. Further, he
would like graph matching of literals to include comparison of values
instead of comparison of the literal forms.

The SPARQL graph matching algorithm requires no inference and
corresponds to Graph Equivalence and Literal Equality from the RDF
Concepts document. However, the queried graph may be the product of
inference or normalization. XPath value comparisons expressed in the
FILTER constraints provide the expressivity the commenter requested.


In objection 6, Bob MacGregor voices a concern that the algebraic
semantics of SPARQL may be incompatible with the declarative semantics
of OWL. In addition, he advocates "eliminating UNBOUND from the
language".
  http://www.w3.org/2001/sw/DataAccess/crq350#algabraicSemantics

It is not clear that a declarative semantics would result in a
different language. The need for a feature like BOUND was identified
in the First Public Working Draft:
  http://www.w3.org/TR/2004/WD-rdf-sparql-query-20041012/#extendedtests
and specified in the second Working Draft:
  http://www.w3.org/TR/2005/WD-rdf-sparql-query-20050217/#func-isBound


The Director is satisfied that the Working Group's SPARQL
specification meets the requirements from the Working Group charter
and that community review shows a critical mass of support despite
these objections.


Features at Risk
================
A grammar change to allow leading digits in the local part of SPARQL
prefixed names was made in response to a comment from Alan Ruttenberg;
this grammar change has been identified as at-risk in the current
draft to gauge implementation feedback during CR.


Since the previous Candidate Recommendation publication, the Working
Group also adopted the REDUCED feature, based on observations of
actual high-performance implementations. Due to the late addition of
this feature to the language, the Working Group decided to mark the
feature at-risk, pending other implementation experience gathered
during CR.


SPARQL Query Results XML Format
===============================
The SPARQL Query Results XML Format is returning to Last Call for
three week in order to simplify the specification by eliminating the
ordered and distinct attributes. The tests for the SPARQL Query
Language also test the SPARQL Query Results XML Format so the Results
Format specification will proceed directly from Last Call to Proposed
Recommendation when SPARQL Query proceeds to Proposed Recommendation.


Patent disclosures
==================
Patent disclosures relevant to this specification may be found on the
Data Access Working Group Working Group's patent disclosure page in
conformance with W3C policy:
  http://www.w3.org/2004/01/pp-impl/35463/status

==============================================
Quoting from the SPARQL Query Language for RDF
W3C Candidate Recommendation - 14 June 2007
==============================================

   SPARQL Query Language for RDF

   W3C Candidate Recommendation - 14 June 2007

   This version:
      http://www.w3.org/TR/2007/CR-rdf-sparql-query-20070614/
   Editors:
      Eric Prud'hommeaux, W3C <eric@w3.org>
      Andy Seaborne, Hewlett-Packard Laboratories, Bristol 
<andy.seaborne@hp.com>

   Copyright  2006-2007 W3C (MIT, ERCIM, Keio), All Rights
   Reserved. W3C liability, trademark and document use rules apply.


   Abstract
   --------
   RDF is a directed, labeled graph data format for representing
   information in the Web. This specification defines the syntax and
   semantics of the SPARQL query language for RDF. SPARQL can be used
   to express queries across diverse data sources, whether the data is
   stored natively as RDF or viewed as RDF via middleware. SPARQL
   contains capabilities for querying required and optional graph
   patterns along with their conjunctions and disjunctions. SPARQL
   also supports extensible value testing and constraining queries by
   source RDF graph. The results of SPARQL queries can be results sets
   or RDF graphs.


   Status of This Document
   -----------------------
   The design has stabilized and the Working Group intends to advance
   this specification to Proposed Recommendation once the exit
   criteria below are met:

    * A test suite gives reasonable coverage of the features of the
      query language.

      Note that the working group has developed a collection of query
      tests in the past, and the group is currently working on
      approving these tests and migrating them to a new location to
      form the basis of an implementation report. This work is still
      in progress.

    * Each identified SPARQL feature has at least two implementations.

    * Relevant media types are registered:

        o The SPARQL Query Language for RDF specification introduces
          one new Internet Media Type. Review has been requested,
          but the types are not yet registered:
            + application/sparql-query: review request of 24 Nov 2005

    * Normative dependencies have been advanced to Proposed
      Recommendation status:
          o XQuery 1.0 and XPath 2.0 Functions and Operators

   This specification will remain a Candidate Recommendation until at
   least 31 August 2007. An implementation report is in progress.

   This specification contains two features at-risk listed both here
   and where the features appear in the specification:

    * The REDUCED feature
    * The allowance of leading digits in prefixed names

   This document was produced by a group operating under the 5
   February 2004 W3C Patent Policy.
      http://www.w3.org/Consortium/Patent-Policy-20040205/
   W3C maintains a public list of any patent disclosures
      http://www.w3.org/2004/01/pp-impl/35463/status
   made in connection with the deliverables of the group; that page
   also includes instructions for disclosing a patent. An individual
   who has actual knowledge of a patent which the individual believes
   contains Essential Claim(s)
      http://www.w3.org/Consortium/Patent-Policy-20040205/
   must disclose the information in accordance with section 6 of the
   W3C Patent Policy.
      http://www.w3.org/Consortium/Patent-Policy-20040205/


The Data Access Working Group Working Group expects to receive more
comments in the form of implementation feedback and test cases. The
Working Group believes it will have satisfied its implementation
criteria by 31 August 2007.

This Call for Implementations follows section 7.4.3 of the W3C Process
Document:
  http://www.w3.org/2005/10/Process-20051014/tr.html#cfi

Thank you,

For Tim Berners-Lee, Director, and
Ivan Herman, Semantic Web Activity Lead;
Susan Lesch, W3C Communications Team





Received on Thursday, 14 June 2007 21:06:21 GMT

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