W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > July to September 2004

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

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Tue, 20 Jul 2004 19:41:39 +0100
Message-ID: <40FD6763.5040104@hp.com>
To: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
Cc: 'RDF Data Access Working Group' <public-rdf-dawg@w3.org>

 > SELECT ?s, ?src
 > WHERE (?s ?p ?o) SOURCE ?src
 >
 > 	+-------+-------+
 > 	| ?s    | ?src  |
 > 	+-------+-------+
 > 	| :foo  | a.rdf |
 > 	| :bar  | b.rdf |
 > 	+-------+-------+

I would have expected

  	+-------+-------+
  	| ?s    | ?src  |
  	+-------+-------+
  	| :foo  | a.rdf |
  	| :foo  | a.rdf |
  	| :bar  | b.rdf |
  	+-------+-------+

without a DISTINCT being added to the query.

	Andy


Steve Harris wrote:

> On Mon, Jul 19, 2004 at 05:21:29PM -0500, Dan Connolly wrote:
> 
>>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.
> 
> 
> I understand it to be (opionally) a set of RDF grpahs. I would like it if
> the intention is that servers that do not need/use source information can
> ignore it, eg. treat all triples as having a single source.
>  
> 
>>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.
> 
> 
> Some trivial ones, BRQLised:
> 
> Data
> 
> a.rdf:
> 	:foo  :a  "a"
> 	:foo  :b  "b"
> 
> b.rdf:
> 	:bar  :a  "a"
> 
> 
> SELECT ?s
> WHERE (?s ?p ?o) SOURCE <a.rdf>
> 
> 	+-------+
> 	| ?s    |
> 	+-------+
> 	| :foo  |
> 	+-------+
> 
> 
> SELECT ?s, ?src
> WHERE (?s ?p ?o) SOURCE ?src
> 
> 	+-------+-------+
> 	| ?s    | ?src  |
> 	+-------+-------+
> 	| :foo  | a.rdf |
> 	| :bar  | b.rdf |
> 	+-------+-------+
> 
> 
> CONSTRUCT * WHERE (?s ?p ?o) SOURCE <a.rdf>
> 
> should return an RDF graph equivalent to the orignal asserted a.rdf I
> think. I dont have a real test for this, but it seems very useful so I
> included it anyway.
> 
> 	+---------------+
> 	| *             |
> 	+---------------+
> 	| :foo  :a  "a" |
> 	| :foo  :b  "b" |
> 	+---------------+
> 
> - Steve
Received on Tuesday, 20 July 2004 14:42:02 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:20 GMT