The RDB2RDF Working Group has published, in September 2012, two Recommendations: “A Direct Mapping of Relational Data to RDF“ and “R2RML: RDB to RDF Mapping Language”. The Working Group has been closed in 2012.

The mission of the RDB2RDF Working Group, part of the Semantic Web Activity, is to standardize languages for mapping relational data and relational database schemas into RDF and OWL. The two languages are the Direct Mapping (DM) and the RDB2RDF Mapping Language (R2RML).

The RDB2RDF Working Group Charter shows what the W3C has asked this working group to do.

RDB2RDF W3C Standards and Notes

• R2RML: RDB to RDF Mapping Language, W3C Recommendation
• A Direct Mapping of Relational Data to RDF, W3C Recommendation
• R2RML and Direct Mapping Test Cases, W3C Editor's Draft
• Use Cases and Requirements for Mapping Relational Databases to RDF, W3C Working Draft

Inputs

• Relational Databases on the Semantic Web, Tim Berners-Lee, Design Issue Note, 1998-2009.
• A Survey of Current Approaches for Mapping of Relational Databases to RDF (PDF), Satya S. Sahoo, Wolfgang Halb, Sebastian Hellmann, Kingsley Idehen, Ted Thibodeau Jr, Sören Auer, Juan Sequeda, Ahmed Ezzat, 2009-01-31.

  This document surveys the current techniques, tools and applications for mapping between Relational Databases (RDB) and Resource Description Framework (RDF). Some knowledge of RDF as well as RDB concepts and technologies is assumed for readers of this document. The survey is intended to enable the members of the W3C RDB2RDF Incubator Group to: (1) collate the existing state of the art in mapping approaches between RDB and RDF, and (2) use the reference framework defined in this survey to effectively compare the different mapping approaches.

• Incubator Group Report, Ashok Malhotra (ed), 2009-01-31.

  This document is the final report from the RDB2RDF XG. The XG recommends that the W3C initiate a WG to standardize a language for mapping Relational Database schemes into RDF and OWL.

• Reusable Identifiers in the RDB2RDF mapping language, Michael Hausenblas and Themis Palpanas.

These are documents produced outside the RDB2RDF Working Group that will be inputs to the standardization work of RDB2RDF WG. Please alert the co-Chairs or Staff Contact of the Working Group if you know of any material that you think merits inclusion.

Schedule of Deliverables

• A specification for languages to map relational data and relational schemas to RDF and OWL (tentatively called R2RML and Direct Mapping) as W3C Recommendations.
• A set of test cases to test conformance. It is up to the Working Group to decide whether it wishes to publish this document as a W3C Recommendation or as a Working Group Note.

Other Deliverables

These are deliverables that the group plans to produce, in line with the scope description above, but only if the time and the available manpower allows it. The Working Group will have to decide whether these documents will be published as Working Group Notes or additional Recommendations.

• An alternate "human-readable" syntax for R2RML.
• A set of profiles for R2RML sufficient to provide specific, simpler functionality.
• An R2RML primer.

Timeline View Summary

• September 2009: First teleconference
• June 2010: First face-to-face meeting
• July 2010: Requirements and Use Cases for the RDB2RDF Mapping Language (R2RML)
• September 2010: First Public Working Draft for R2RML
• September 2010: First Public Working Draft for DM
• March 2011: First Public Working Draft for R2RML Test Cases
• March 2011: First Public Working Draft for DM Test Cases
• September 2011: R2RML Syntax - Last Call
• September 2011: DM Semantics - Last Call
• December 2011: R2RML Syntax - Candidate Recommendation
• December 2011: DM Semantics - Candidate Recommendation
• January 2012: R2RML Test Cases - Last Call
• January 2012: DM Test Cases - Last Call
• March 2012: R2RML Syntax - Proposed Recommendation
• March 2012: DM Semantics - Proposed Recommendation
• June 2012: R2RML Syntax - Recommendation
• June 2012: DM Semantics - Recommendation
• March 2012: R2RML Test Cases - Final Version
• March 2012: DM Test Cases - Final Version

The working group schedule is an estimate based on the schedule in the charter and subject to negotiation with peer groups via the Semantic Web Coordination Group.

Group Membership and Joining

We encourage new members of the group to introduce themselves by email. The full RDB2RDF WG participants list is available to W3C members.

If you want to join the group:

• If you're affiliated with a W3C member organization
  1. Use the form for getting a W3C account
  2. Have your AC representative nominate you using the form for joining this WG.
• Otherwise, contact the chair and team contact about invited expert status. That will involve getting an account and filling out a form for copyright, patent, etc. policies.

Meeting Records

The meeting records are maintained on a dedicated Wiki page ...

RDB2RDF history

These events pre-date the RDB2RDF Working Group:

• 2008/2009: RDB2RDF Incubator Group
• 25-26 October, 2007: W3C Workshop on RDF Access to Relational Databases

W3C Working Group Resources

• Art of Consensus Guide W3C member confidential
• World Wide Web Consortium Process Document 14 October 2005
• W3C Groups, Participants (dbwg) W3C member confidential