Proposed SPARQL Working Group Charter, Revised

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 SPARQL Working Group, part of the Semantic Web Activity, is to produce a Working Group Note identifying requirements for an extension of SPARQL. The extension is a small set of additional features 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

No Recommendation Track documents will be produced under this charter. The requirements specified in the Group Note will be used to create a new charter proposal for a Phase II of the work, whose ultimate goal will be to produce a new SPARQL Recommendation.

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 may form the basis of this extension, but the Working Group will also consider other submissions.

Join the SPARQL Working Group.

End date	30 July 2009
Confidentiality	Proceedings are public
Initial Chairs	Lee Feigenbaum Axel Polleres
Initial Team Contacts (FTE %: 30)	Eric Prud’hommeaux (20%) Ivan Herman (10%)
Usual Meeting Schedule	Teleconferences: Weekly Face-to-face: 1

Scope

Although the community has expressed opinions on various types of extensions to SPARQL, this Working Group is only chartered to enumerate a set of extensions 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 propose a significant upgrade of the SPARQL language. Examples for the extensions to the SPARQL, 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.
Examine options for a more predictable DESCRIBE functionality.
Reconsider the issue on XML Serialization of the SPARQL query language (this issue was explicitly postponed by the previous DAWG group).

Note that this charter does not mandate which extensions to SPARQL the Working Group will select. The task of the group, documented as its deliverable (see the section on Milestones below) is to produce a final and prioritized list of extensions that the group proposes. This deliverable will become the basis for a new charter to undertake Recommendation Track work.

The group will also take into consideration the errors on the documents reported by the community since the publication 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.

Deliverables

(The title of the document is indicative only)

SPARQL Features & Rationales: list of extensions to be added to the January 2008 version of SPARQL. The document should also prioritize the items as input to subsequent work under a new charter. This Features & Rationales document is to be published as a Working Group Note.

Milestones

The Working Group is chartered to deliver one document, in the form of a Working Group Note, tentatively entitled “SPARQL Features and Rationales”.

Timeline View Summary

May 2009: SPARQL Features & Rationales, First public draft
July 2009: SPARQL Features & Rationales, Working Group Note
August 2009: Charter proposal for Phase II under AC Review

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: If the SPARQL Working 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 SPARQL Working Group is expected to have 10 or more active participants for its duration. Effective participation to SPARQL Working Group is expected to consume one work day per week for each participant; two days per week for editors.

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

Communication

This group primarily conducts its work on the public 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 SPARQL 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 SPARQL 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: 2009/06/01 22:19:26 $