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Re: SWObjects slides for Tue

From: Eric Prud'hommeaux <eric@w3.org>
Date: Mon, 7 Dec 2009 18:32:47 -0500
To: public-rdb2rdf-wg@w3.org, Alexandre Bertails <bertails@w3.org>
Message-ID: <20091207233246.GB11174@w3.org>
* Eric Prud'hommeaux <eric@w3.org> [2009-12-05 17:16-0500]
> I'll be working on this more, but here's a start on the slides
> introducing algebra for RDB->RDF and (corresponding) SPARQL->SQL
> mappings.

I broke the link on the wiki (pointed to my laptop).
covers everything I want to tomorrow. I've covered
most of the algebra differences between SPARQL over
an SQL triples view and SPARQL over generic (e.g. 3FN)
relational data.

I know that a lot of this requires the narrative in
my head, but if anyone notices something conspicuously
absent by tomorrow's call, let me know.

>           If folks want to play with this stuff, try downloading
> the appropriate SPARQL from
>   http://sourceforge.net/projects/swobjects/files/
> and executing "SPARQL -s http://hr.example/DB/ -e
>    "PREFIX emplP: <http://hr.example/DB/Employee#>
>     SELECT ?empName ?managName
>      WHERE { ?emp emplP:lastName ?empName .
>              ?emp emplP:manager ?manager .
>              ?manager emplP:lastName ?managName }"
> You should see:
> SELECT emp.lastName AS empName, manager.lastName AS managName
>        FROM Employee AS emp
>             INNER JOIN Employee AS manager ON manager.id=emp.manager
> which corresponds closely (modulo NULLs) to the results expected in
>   http://www.w3.org/2008/07/MappingRules/StemMapping#bgp1
> The pitch is that this is a doable and useful task and that the world
> will buy us many beers for accomplishing this.
> -- 
> -ericP

Received on Monday, 7 December 2009 23:33:23 UTC

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