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Re: on log:definitiveService

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 21 Feb 2005 13:22:41 +0000
Message-ID: <4219E0A1.70008@hp.com>
To: Dan Connolly <connolly@w3.org>
CC: RDF Data Access Working Group <public-rdf-dawg@w3.org>

Dan Connolly wrote:
> On Mon, 2005-02-14 at 08:52 -0600, Dan Connolly wrote:
> 
>>re ACTION: DanC to Write up definitive service concept
>>
>>Darn... I thought it was written up in
>>  http://www.w3.org/2000/10/swap/doc/Reach
>>but on review, I see it isn't.
> 
> 
> OK, somebody reminded me of the tests EricP and
> I worked on a while ago...
>   http://www.w3.org/2000/10/swap/test/dbork/
> 
> but we don't have a write-up, so here goes...
> 
> In OrderTracking1.n3 , we see...
> 
> <mysql://rdftest@swada.w3.org/OrderTracking/>
>   is log:definitiveService of
>     Orders:id, Orders:customer, Orders:product,
>     Orders:orderDate ...
> 
> The idea is that if you've got a query ala
> 
>  SELECT ?productName, ?first, ?last
>  WHERE 
>  (?o Orders:customer ?c)
>  (?o Orders:product ?p)
>  (?o Orders:orderDate ?d)
> 
>  (?p Products:name :productName)
> 
>  (?c Customers:familyName ?first)
>  (?c Customers:givenName ?last)
> 
> Then, since each of the properties in the query
> is connected to <mysql://rdftest@swada.w3.org/OrderTracking/>
> by log:definitiveService , you can delegate the query there;
> i.e. if there are any answers to be found, that service has
> them. It's definitive.
> 
> I expect lots of SPARQL services are interfaces to SQL
> databases, where the data in that SQL database is definitive.
> It's the customer database or whatever. All of widgetCo's
> customers are in there; they have the power to close that
> part of the world.

Minor but there isn't often one such database in a WidgetCo.  A major source of 
IT projects is just such data integration exercises.

Even small companies have maultiple places - e.g. a sales person's list of 
customers and the order department.

What they need is a semantic web ...

 >  Or it's a database of my CDs. I'm
> the authority on which CDs are in my collection, so I
> can reasonably publish a description of, say, my desktop
> SPARQL query service using log:definitiveService .
> 
> 
> Other examples in that /dbork/ directory demonstrate federated
> query, where cwm will look at a query, realize that it
> can be split into parts that can be handled by remote services,
> delegate to them, and collect the results. I think our
> implementation used the mysql protocol as a network protocol.
> That's obviously to be replaced by the SPARQL protocol.
> 
> So that's the idea, on the front side of one page. Does
> it merit more investigation?
> 

Yes - :definitiveService seems to be to be a very important piece of information 
to support federated query and query routing.

I don't see that it as an absolute requirment for the WG's service description 
at this stage though - if it is ready, then yes, put it in; if it feels it needs 
some refinement by usage then I would not see the LC process being held up for it.

	Andy
Received on Monday, 21 February 2005 13:24:22 GMT

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