This page is for collecting ideas about what the CG should recommend to the W3C. Please comment.

Recommendation

The W3C should start a WG to create a standard for a Property Graphs data model. A charter is outlined below.

Charter Outline

Property Graphs is an increasingly popular data model that has applications in several areas. Recently, Property Graphs have been given added impetus by social media such as Facebook, LinkedIn and Twitter. Social Media data is naturally represented as Property Graphs and social media companies store increasingly large volumes of data and mine it for various purposes. The purpose of this Working Group is to create a standard for a Property Graphs data model which will facilitate the representation and analysis of Property Graph data and help integrate such data with other data on the Web.

The WG will also discuss whether to start another W3C activity to standardize a Property Graphs API.

• End date: December 2014 or 8 months after inception.
• Confidentiality: Proceedings will be public
• Initial chair: Ashok Malhotra (Oracle)
• Initial team contact (FTE % 1 to 2): TBD
• Usual Meeting Schedule: (Weekly teleconferences. 2 face to face meetings.)

Scope and Deliverables

A Data Model for Property Graphs

The goal of the WG is to standardize a data model for Property Graphs. The main deliverable of the WG will be a recommendation that describes a data model for Property Graphs in detail.

Property Graphs is a node (vertex) and edge (link) model in which both nodes and edges can have properties. But we need to decide some details such as should nodes be typed; what datatypes can the properties have; whether to support multi-valued properties, etc. It has also been suggested that the data model include collection types such as sets and bags.

Property Graphs will often be used to model data for a particular domain. Thus, it is important for the data model be able to use attributes from that domain. This requires, at a minimum, the ability to use URIs that designate attribute names from that domain. Schema.org is an example.

It would be useful to be able to identify nodes, graphs and subgraphs by URIs to allow graphs and subgraphs to be shared. Use of URIs in the data model would also help integrate Property Graph data with other data on the Web.

Serialization Format

To test the specification and facilitate exchange of models the WG should agree on a simple exchange format, perhaps similar to N-Triples for RDF. Clearly, there will be several serialization formats for Property Graphs optimized for different usecases. This is outside the scope of the suggested WG and such formats will continue to be developed independently.

Test Cases

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.

Optional Deliverables

Proposal for a REST-based Navigational API for Working with Property Graphs

Property Graph APIs tend to be navigational. A REST-based API would mint URIs for collections of nodes and edges, allow navigation to connected nodes and edges and selection by attribute value, etc. OData and REXSTER are examples of this kind of API. The WG may create a proposal for such a language which could be pursued in a subsequent WG.

Proposal for a Declarative Query Language for Property Graphs

Considerable interest has been expressed in a declarative query language for Property Graphs. The WG may create a proposal for such a language which could be pursued in a subsequent WG.

Investigate Relationship of RDF to Property Graphs

See, for example, Gregg Kellogg proposal. The WG may want to discuss the relationship of Property Graphs to RDF e.g. how to represent Property Graphs in RDF or extend RDF to accommodate Property Graphs.

Out of Scope

• An API for working with Property Graphs.
• Specific Property Graph analysis algorithms.

Success Criteria

• Timely preparation of the deliverables.
• At least two implementations of the data model that conform to the recommendation and successfully pass the test cases. The data model implementations will typically be embedded into products that provide additional functionality.

Timeline

• First teleconference: April 2014
• FPWD: July 2014
• LCWD: Sept 2014
• Recommendation: December 2014

Dependencies

TBD

Participation

To be successful, the Property Graphs Working Group is expected to have 5 or more active participants for its duration. Effective participation to Working Group is expected to consume one work day per week for each participant; two days per week for editors. The Property Graphs Working Group will allocate also the necessary resources for building Test Suites for each specification.

Communication

This group primarily conducts its work on the public mailing list [List name]. [Provide information about additional Member-only lists that are used for administrative purposes.]

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

Decision Policy

As explained in the Process Document Process (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

The Property Graphs Working Group will operate under the 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 Status Page.

About this Charter

This charter for the Property Graphs 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.