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Re: Mapping SPARQL to SQL

From: Ivan Mikhailov <imikhailov@openlinksw.com>
Date: Sun, 06 Apr 2008 01:30:07 +0700
To: ashok.malhotra@oracle.com
Cc: public-xg-rdb2rdf <public-xg-rdb2rdf@w3.org>
Message-Id: <1207420207.3275.45.camel@master.iv.dev.null>

Hello Ashok

I'm writing SPARQL-to-SQL front-end of Virtuoso Universal Server /
Virtuoso Open Source ( http://virtuoso.openlinksw.com ) . We treat
SPARQL as a syntax extension of SQL so we allow SPARQL queries in any
place where SQL subquery may appear in a stored procedure or in a client
request via ODBC or the like. We also provide SPARQL web service
endpoint, SPARUL extension and various SPARQL extensions for business
intelligence, like SPARQL subqueries.

Some brief descriptions of mapping are in
http://www.openlinksw.com/virtuoso/Whitepapers/html/rdf_views/virtuoso_rdf_views_example.html
and
http://virtuoso.openlinksw.com/wiki/main/Main/VOSSQLRDF

The 'native' RDF storage in Virtuoso is just a 4-column table (G,S,P,O)
that is 'mapped to RDF' one-to-one, but it's just a mapping without any
special privileges so we freely mix native RDF data with relational.

We also provide "RDF Sponge" extensions so the server may download
missing RDF data from remote RDF resources, including downloading
non-RDF resources and extracting metadata by various extraction tools.

Best Regards,

Ivan Mikhailov,
OpenLink Software.

On Sat, 2008-04-05 at 08:47 -0700, ashok malhotra wrote:
> Do any of you know about or have been involved in work that maps SPARQL 
> queries to SQL?
> I'm assuming a Relational database that has been mapped virtually to 
> RDF.  SPARQL Queries
> on the RDF representation would need to be translated to SQL queries on 
> the underlying Relational database.
> 
Received on Saturday, 5 April 2008 18:31:24 GMT

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