W3C

- DRAFT -

RDB2RDF Telcon Dec 12, 2008

12 Dec 2008

See also: IRC log

Attendees

Present
Ashok_Malhotra, Andrew_Eisenberg, Satya, Soeren, Wolfgang, Orri Erling, Ivan Mikhailov, Ahmed Ezzat
Regrets
Juan Sequeda, Axel Polleres, Jenny Green
Chair
Ashok Malhotra
Scribe
Soeren

Contents


 

 

<Ashok> scribenick, Soeren

Approval of Minutes

minutes for 5th of Dec are approved

XG Logistics

next meeting 3 meetings canceled

next meeting will be 9th of Jan 2009

Action Items

Mail sent but no responses yet from Bijan and ChrisB. Actions closed.

satya will send state-of-the-art document in first week of Jan

satya requests timeslot for presentation about mapping clinical data to RDF

<Ashok> Satya will contact Susie Stephens

no discussions about RIF today. Axel Polleres not on call.

Presentation of XG Progress to Semantic Web Gathering at MIT

Ashok reports about Semantic Web gathering last Tuesday

takes place regularly at MIT and organized by Kingsley

Ashok reports about positive feedback

Sandro Hawke from W3C supports use of RIF to specify mapping language

Creative Commons aims at starting a common naming workgroup

... similar to ENS (and LSID)

There was a request from W3C that use cases should be referenced from the recommendation

Orri: integration and interoperability justify the need for a mapping language

http://linkedgeodata.org/

Soeren Reports on Linked Geo-Data

<Ashok> Data from Open Street Maps

<Ashok> Distributed World Wide Community ... anyone can contribute

<Ashok> Data can be published as RDF. They use Triplify

http://linkedgeodata.org/browser/

<Ashok> There is also a facet-based browser for this data

<Ashok> can search for bicycle-shops for example

<Ashok> Relational data structure but close to RDF

OSM schema consists of relations and RDF like structures

<Ashok> Each point and way has a unique ID

points and ways are tagged with property value combinations

<Ashok> That is FK into a tag table ... which has Mant-to-Many Rels from point to way ... 1 to M from Way to Tag

<Ashok> Soeren property-value annotations on each point or way

<Ashok> People shd try it out .... still work in progress ... setting up Wiki etc.

<Ashok> Data is open, people can add and modify it... can create own properties and, in fact, new applications

<Ashok> There is a website called MapMyRun which tells you where you can run anywhere in the world.

<iv_an_ru> (Alan Ruttenberg should look at linkedgeodata. By replacing Earth map with X-Ray snapshot of, say, brain, he may get an interesting tutorial application)

OSM applies the wiki approch to geo data

<Ashok> Can be more detailed. Depends on the community. Liepzig and London are very detailed. Much more info than Google Maps

Ivan Mikhailov on Ordance Survey Usecase

Ivan sent email on the ordenance survey use case

http://lists.w3.org/Archives/Public/public-xg-rdb2rdf/2008Nov/0027.html

Orri: mapping geographical joining requires special SPARQL support

OpenLink will look into the ordinance survey use case once logistics are clarified

one week of work for OpenLink (after setup of the infrastructure) to create a showcase on using SPARQL for handling ordinance survey geo data

Orri estimates most workload can be pushed down into the DB

<Ashok> ACTION: Orri to write up Ordnance Survey Usecase by early January. Discuss on Jan 9 telcon. [recorded in http://www.w3.org/2008/12/12-RDB2RDF-minutes.html#action01]

XG Recommendation

talk about XG recommendation

<Ashok> http://esw.w3.org/topic/Rdb2RdfXG?action=AttachFile&do=view&target=ProposedRecommendation

<scribe> ACTION: Ashok will send recommendation draft to mailing list [recorded in http://www.w3.org/2008/12/12-RDB2RDF-minutes.html#action02]

<Ashok> Ahmed: How about a JDBC like interface that takes a SPARQL query and refurns RDF

<iv_an_ru> Why "JDBC like"? Use JDBC...

Orri says SPARQL and SQL can be mixed and used together

SQL should be writeable inside SPARQL

<iv_an_ru> If needed, I'll implement that quickly

DAWG working group exists

<iv_an_ru> Actually, some SQL fragments appear in our mapping rules already, so the required infrastructure is in place.

fairly limited scope right now in DAWG

<Ashok> Orri: Put a SQL view in SPARQL instead of graph-pattern

<Ashok> SPARQL must have views and these may be SQL-views

Satya asks whether a SPARQL view can be considered as a sub-graph

<Ashok> Orri: It would be a derived table

in-completeness of SPARQL complicates the problem

<scribe> ACTION: Ashok we remind on the public list on documents for review by the group [recorded in http://www.w3.org/2008/12/12-RDB2RDF-minutes.html#action03]

next meeting 9th of Jan 2009

<Ashok> Soeren: Result of SPARQL query is not always a graph ... SPARQL does not have relational completeness. Not easy to acheive.

Ahmed Ezzat reminded us in email that his words were not captured accurately above. He offers the following clarification:

My statement was to provide a capability from SPARQL level to call any data source with the query to that data source expressed as a string, and passing SPARQL endpont-id to interpret the string correctly at lower layers. It is below that level where JDBC comes in the picture for SQL data sources.

I shared the above in the context of SPARQL WG (Andy Seaborne from HPL Bristol was talking with me about adding capabilities to SPARQL) as well as to point out that RDB2RDF mapping will not be visible to the SPARQL programmer. In this later context I used JDBC where mapping SQL data types to Java is done in the driver. As a follow up on comment that Java is not a query language, I stated that stored procedures are called from a query language and that can call other target languages and the mapping is still transparent to the SQL application.

This is an alternative to generating the SQL from SPARQL automatically (query rewrite); I think both models should be supported as data sources are not limited to SQL only. Mixing SQL and SPARQL (Oralce style) and earlier mixing SQL and Xquery (IBM DB2 9 - code name Viper) is different as they approach the problem from SQL point of view while SPARQL should have generic approach (SQL is most important but not the only data source).

Summary of Action Items

[NEW] ACTION: Ashok we remind on the public list on documents for review by the group [recorded in http://www.w3.org/2008/12/12-RDB2RDF-minutes.html#action03]
[NEW] ACTION: Ashok will send recommendation draft to mailing list [recorded in http://www.w3.org/2008/12/12-RDB2RDF-minutes.html#action02]
[NEW] ACTION: Orri to write up Ordnance Survey Usecase by early January. Discuss on Jan 9 telcon. [recorded in http://www.w3.org/2008/12/12-RDB2RDF-minutes.html#action01]
 
[End of minutes]

Minutes formatted by David Booth's scribe.perl version 1.133 (CVS log)
$Date: 2008/12/12 17:09:05 $

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Present: Ashok_Malhotra Andrew_Eisenberg Satya Soeren Wolfgang [IPcaller] iv_an_ru
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People with action items: ashok draft orri recommendation send will

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