This charter is now obsolete, has been superceded by the renewed group charter.

RDB2RDF Working Group Charter

The mission of the RDB2RDF Working Group, part of the Semantic Web Activity, is to standardize a language for mapping relational data and relational database schemas into RDF and OWL, tentatively called the RDB2RDF Mapping Language, R2RML.

From the beginning of the deployment of the Semantic Web there has been increasing interest in mapping relational data to the Semantic Web. This is to allow relational data to be combined with other data on the Web, to link semantics directly to relational data and to aid in enterprise data integration. In October 2007 the W3C organized a workshop on RDF Access to Relational Databases. This led to the formation of the RDB2RDF Incubator Group to explore the area. This Incubator Group concluded its work in February 2009 having produced two deliverables: a Survey of the State of the Art and a RDB2RDF XG Final Report. The RDB2RDF XG Final Report recommends that the W3C initiates a Working Group to standardize a language for mapping relational database schemas to RDF and OWL. This charter is in response to that recommendation.

The mapping language defined by the WG will facilitate the development of several types of products. It could be used to translate relational data into RDF which could be stored in a triple store. This is sometimes called Extract-Transform-Load (ETL). Or it could be used to generate a virtual mapping that could be queried using SPARQL and the SPARQL translated to SQL queries on the underlying relational data. Other products could be layered on top of these capabilities to query and deliver data in different ways as well as to integrate the data with other kinds of information on the Semantic Web. The RDB2RDF XG Final Report includes several detailed usecases that motivate the mapping language.

Join the RDB2RDF Working Group.

End date 30 September 2011
Confidentiality Proceedings are public
Initial Chairs Ashok Malhotra (Oracle)
Michael Hausenblas (DERI)
Team Contacts
(FTE %: 15)
Ivan Herman
Usual Meeting Schedule Teleconferences: Weekly
Face-to-face: up to 3 per year, as agreed by the participants


Based on the Survey of Current Approaches for Mapping of Relational Databases to RDF prepared by the RDB2RDF XG and the RDB2RDF XG Final Report the scope of R2RML is defined as follows:

The Survey of the State of the Art describes several languages and implementations that may be used as starting points for the work of the WG.

Success Criteria

Out of Scope


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.


Specification transition estimates. (“T” denotes the starting month of the Working Group.)

Note: The group will document significant changes from this initial schedule on the group home page.
Specification FPWD LC CR PR Rec or WG Note
R2RML T+6 T+18 T+20 T+22 T+24 (Rec)
R2RML Test cases T+14 T+19     T+24 (Status to be decided)

Timeline View Summary

“T” denotes the starting month of the Working Group.


W3C Groups

SPARQL Working Group
Track the evolution of SPARQL (updates, etc.).
Possibly define a dialect of RIF for the mapping language.
The HTML 5 spec has a section on possible database access.
Health Care and Life Sciences IG
To gain further use case requirements and communicate with a major user community

Furthermore, RDB2RDF Working Group expects to follow these W3C Recommendations:

External Groups

Linked Data community
To support the implementation of the linked data principles.
The OKKAM Project
The ENS System for assigning reusable identifiers to people, locations, organizations, events, products, etc.
Neuro Commons Common Naming Project
Reusable identifiers for life sciences entities.


To be successful, the RDB2RDF Working Group is expected to have 5 or more active participants for its duration. Effective participation to RDB2RDF Working Group is expected to consume one work day per week for each participant; two days per week for editors. The RDB2RDF 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.


This group primarily conducts its work on the public mailing list public-rdb2rdf-wg@w3.org.

Information about the group (deliverables, participants, face-to-face meetings, teleconferences, etc.) is available from the RDB2RDF 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.

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 RDB2RDF 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.

Ivan Herman, Staff Contact and Semantic Web Activity Lead

$Date: 2011/11/17 11:34:26 $