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Re: Objective 4.2 : Change "provenance" to "data management"

From: Dan Connolly <connolly@w3.org>
Date: Mon, 19 Jul 2004 17:21:29 -0500
To: Kendall Clark <kendall@monkeyfist.com>
Cc: Andy Seaborne <andy.seaborne@hp.com>, 'RDF Data Access Working Group' <public-rdf-dawg@w3.org>
Message-Id: <1090275688.14421.1315.camel@dirk>

On Mon, 2004-07-19 at 17:06, Kendall Clark wrote:
> On Mon, Jul 19, 2004 at 08:06:21PM +0100, Seaborne, Andy wrote:
> 
> > """
> > 4.2. Support for RDF Aggregation Graphs
> > 
> > RDF can be used for data integration and aggregation where an RDF repository
> > is built by merging RDF triples from several other RDF repositories or from
> > non-RDF source converted to RDF.  Such an aggregation can be real or
> > virtual.  
> > 
> > In such an RDF graph, the query client may wish to know where the target
> > server originally collected a triple or subgraph from.  The query language
> > and protocol should enable an RDF repository to expose such information.
> > """
> 
> Modulo some (minor) wording changes and some consolidation of the two
> paragraphs, I support this reworking of 4.2. As I said in Carlsbad,
> for building real world apps, some kind of data management (variously
> known as 'provenance', 'contexts', and 'source') is essential.

Can that data management support be deployed in each application as
it sees fit? Or is there some case for an interoperable mechanism?


> To address Rob's point, I don't see 4.2 as contradicting or extending
> the RDF data model. 

Perhaps the objective is fuzzy enough so that the conflict isn't
clear, but all the concrete designs I have seen
(e.g. the BRQL SOURCE mechanism) involve the input to the QUERY
being more than just an RDF graph.

The spec doesn't yet explicitly say what the input to a query
is, but it seems to be more than just a graph:

"The SOURCE clause added to a triple pattern causes the variable or
literal to match or bind the RDF graph which the statement came from, if
the server knows."
 -- http://www.w3.org/2004/07/08-BRQL/
 $Revision: 1.14 $ of $Date: 2004/07/19 13:11:51 $

Does anybody have any test cases for SOURCE? I'm sure those would
make this crystal clear.



> 
> I'll be moving something very much like Andy's wording into the UC&R
> document when I next update it (very soon).
> 
> Best,
> Kendall
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Monday, 19 July 2004 18:20:59 GMT

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