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ACTION: a replacement for 4.5 focussed on union query

From: Simon Raboczi <raboczi@tucanatech.com>
Date: Tue, 27 Jul 2004 03:22:00 -0700
Message-Id: <CBE55F72-DFB6-11D8-8061-000A95C5686E@tucanatech.com>
To: public-rdf-dawg@w3.org

The current (CVS revision 1.128) text is
[[
4.5 Aggregate Query

It should be possible to specify two or more RDF graphs against which a  
  query shall be executed; that is, the result of an aggregate query is  
the  merge of the results of executing the query on each of two or more  
  graphs.
]]

Previous discussion about "aggregate query" versus "union query"  
occurred in a thread starting from [1].

We can build on top of the "merge" defined in RDF Semantics[2], and the  
guarantee that "a set of graphs can be treated as equivalent to its   
merge, i.e. a single graph, as far as the model theory is concerned."   
I suggest text as follows:
[[
4.5 Querying multiple sources

It should be possible for a query to specify which of the available RDF  
graphs it is to be executed against.  If more than one RDF graph is  
specified, the result is as if the query had been executed against the  
merge[3] of the specified RDF graphs.
]]

Processors with a single available RDF graph should trivially satisfy  
this objective.


[1]  
http://lists.w3.org/Archives/Public/public-rdf-dawg/2004AprJun/ 
0777.html
[2] http://www.w3.org/TR/rdf-mt/
[3] http://www.w3.org/TR/rdf-mt/#graphdefs
Received on Tuesday, 27 July 2004 06:22:54 GMT

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