RDF Data Access Working Group Charter

Status: version to be reviewed by the AC.

The RDF Data Access Working Group has published three SPARQL recommendations (Query Language, Protocol, and Results Format) in January 2008. SPARQL has become very widely implemented and used since then (and, in fact, even before the specification achieved a W3C Recommendation status). Usage and implementation of SPARQL have revealed requirements for extensions to the query langauge that are needed by applications. Most of these were already known and recorded when developing the current Recommendation, but there was not enough implementation and and usage experience at the time for standardization. Current implementation experience and feedback from the user community makes it now feasible to handle some of those issues in a satisfactory manner.

The mission of the RDF Data Access Working Group, part of the Semantic Web Activity, is to produce a W3C Recommendation that extends SPARQL. The extension is a small set of additional feature that

have been identified by the users as badly needed for applications, and
have been identified by SPARQL implementers as reasonable and feasible extension to current implementations

Note that a strict backward compatibility with exisiting SPARQL design should be mantained, and currently no radical redefinition of the SPARQL language is envisaged. The list of postponed issues, the minutes of a SPARQL WWW2008 BOF meeting held in Beijing, China, in April 2008 (see also an more detailed writup of the same meeting), the community’s discussion results documented on W3C’s ESW Wiki, or the SPARQL Update member submission and the team comments thereof will form the basis of these extensions, but the Working Group will also consider other submissions.

Join the RDF Data Access Working Group. @@@The link may change when the group starts@@@

End date	31 July 2010
Confidentiality	Proceedings are public
Initial Chairs	Lee Feigenbaum [+ 2nd person TBD]
Initial Team Contacts (FTE %: 50)	Eric Prud’hommeaux (20%) Ivan Herman (10%)
Usual Meeting Schedule	Teleconferences: Weekly Face-to-face: 2-3 per year

Scope

Although the community has expressed opinions on various types of extensions to SPARQL, this Working Group is only chartered to make additions that are expected to be widely used and can be shown to exist in multiple, interoperable implementations. It is not the goal of this working group to make a significant upgrade of the SPARQL language. Examples for the extensions to the SPARQL Query Language, to be considered by this Working Group, include:

Insert, update, and delete: building on SPARQL to modify RDF data stores, including using HTTP Post
Query constructs to access container and collection members
Aggregate functions (e.g. COUNT, SUM, MIN, MAX, ...) and supporting query language constructs (e.g. GROUP BY clause, HAVING clause, and the ability to project named expressions)
Additional filters and operators (e.g., full-text search, string functions)
Interoperability mechanisms (e.g., via service descriptions) for endpoints that extend SPARQL basic graph matching to other entailment regimes such as RDF Schema or OWL.

Note that this charter does not mandate which extensions to SPARQL the Working Group will specify. The first task of the group, documented as its first deliverable (see the section on Milestones below) is to produce a final and prioritized list of extensions that the group will indeed handle. Other extensions may be documented to be proposed for a possible future Working Group working on new releases of SPARQL.

The group will also take into consideration the errors on the documents reported by the community since the publication of of the SPARQL documents in January 2008, and stored in the public archives of the relevant mailing list.

Backwards compatibility with the current version of SPARQL is of great importance. All queries, that are valid in the January 2008 version of SPARQL, should remain valid in the new version and should produce identical results. For each new feature, if there is doubt or a perceived problem with respect to this, the guideline should be to not include the feature in the set of extensions.

Out of Scope

It is not in the scope of this Working Group to change the syntax or the semantics of the January 2008 version of SPARQL.

Deliverables

(The titles of the documents are indicative only)

RDF Data Access Use Cases and Requirements, version 2: list of extension categories to be added to the January 2008 version of SPARQL. The document should also prioritize the items, with the possibility to drop some items from the final Recommendation in case the Working Group runs out of time. This document is not expected to be on a Recommendation track.
SPARQL Query Language for RDF, new version, Recommendation.
SPARQL Protocol for RDF, new version, Recommendation.
SPARQL Query Results XML Format, new version, Recommendation.
Serializing SPARQL Query Results in JSON, new version, Working Group Note.

Note that it is not clear at the time of writing the charter whether there is indeed a need to issue new versions of the SPARQL Protocol and Results Format Recommendations. This depends on the list of extensions that the Working Group adopts.

Milestones

Milestones
Specification	FPWD	LC	CR	PR	Rec
Note: The group will document significant changes from this initial schedule on the group home page.
SPARQL Use Cases and Requirements	March 2009
SPARQL Query Language, new version	April 2009	January 2010	March 2010	May 2010	June 2010
SPARQL Protocol, new version	April 2009	January 2010	March 2010	May 2010	June 2010
SPARQL Return XML Format, new version	April 2009	January 2010	March 2010	May 2010	June 2010

Timeline View Summary

T: First teleconference
T+1: RDF Data Access Use Cases and Requirements, version 2, First public draft
T+2: First face-to-face meeting (optional)
T+3: First public Working Draft for Recommendation track documents
T+6: Second face-to-face meeting (optional)
T+10: Third face-to-face meeting (optional)
T+11: Last Call Working Draft for Recommendation track documents
T+13: Fourth face-to-face meeting (optional)
T+14: First Working Draft for the JSON result format Working Group Note
T+14: Candidate Recommendation for Recommendation track documents
T+16: Fifth face-to-face meeting (optional)
T+16: Publication of the JSON result format Working Group Note
T+16: Proposed Recommendation for Recommendation track documents
T+17: Recommendation for all three Recommendation track documents

Dependencies

W3C Groups

Semantic Web Coordination Group: To ensure synchronization with all other Working and Interest Groups in the Semantic Web Activity
OWL Working Group: In case the DAWG group includes, as part of the final list of extensions to SPARQL, interoperability measures with OWL inference regimes, the details should be checked with the OWL group.
Internationalization Activity: To ensure that any extension to string related filters and operators would work in an international setting
XML Query Working Group: To take into account possible extensions and changes in the specification of the XQuery 1.1/XPath Functions & Operators, and experiences in the XQuery Update Facility work.

Furthermore, RDF Data Access Working Group expects to follow these W3C Recommendations:

Participation

To be successful, the RDF Data Access Working Group is expected to have 10 or more active participants for its duration. Effective participation to RDF Data Access Working Group is expected to consume one work day per week for each participant; two days per week for editors. The RDF Data Access Working Group will allocate also the necessary resources for building Test Suites for each specification.

Participants are reminded of the Good Standing requirements of the W3C Process.

Communication

This group primarily conducts its work on the Member-only mailing list public-rdf-dawg@w3.org (with a publicly visible archive) .

Information about the group (deliverables, participants, face-to-face meetings, teleconferences, etc.) is available from the RDF Data Access Working Group home page.

Decision Policy

As explained in the Process Document (section 3.3), this group will seek to make decisions when there is consensus. When the Chair puts a question and observes dissent, after due consideration of different opinions, the Chair should record a decision (possibly after a formal vote) and any objections, and move on.

When deciding a substantive technical issue, the Chair may put a question before the group. The Chair must only do so during a group meeting, and at least two-thirds of participants in Good Standing must be in attendance. When the Chair conducts a formal vote to reach a decision on a substantive technical issue, eligible voters may vote on a proposal one of three ways: for a proposal, against a proposal, or abstain. For the proposal to pass there must be more votes for the proposal than against. In case of a tie, the Chair will decide the outcome of the proposal.
This charter is written in accordance with Section 3.4, Votes of the W3C Process Document and includes no voting procedures beyond what the Process Document requires.

Patent Policy

This Working Group operates under the W3C Patent Policy (5 February 2004 Version). To promote the widest adoption of Web standards, W3C seeks to issue Recommendations that can be implemented, according to this policy, on a Royalty-Free basis.

For more information about disclosure obligations for this group, please see the W3C Patent Policy Implementation.

About this Charter

This charter for the RDF Data Access Working Group has been created according to section 6.2 of the Process Document. In the event of a conflict between this document or the provisions of any charter and the W3C Process, the W3C Process shall take precedence.

Please also see the previous charter for this group.

Eric Prud’hommeaux, Ivan Herman

$Date: 2008/11/11 09:50:37 $