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Re: ISSUE-20: SPARQL Update: Empty vs non-existent graphs

From: Steve Harris <steve.harris@garlik.com>
Date: Fri, 8 Jan 2010 11:09:29 +0000
Cc: Andy Seaborne <andy.seaborne@talis.com>, SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <C58EC636-E204-48A7-A9F7-493E109CD8DB@garlik.com>
To: Paul Gearon <gearon@ieee.org>
On 7 Jan 2010, at 21:06, Paul Gearon wrote:
>
>> Some related issues in update are about adding triples into an  
>> empty graph
>> vs a non-existent graph (does it automatically get created?)
>
> I'd rather not. If this is needed then it can be done with:
>  CREATE SILENT <uri>
>  INSERT DATA { GRAPH <uri> { triples } }

I have a very strong preference for not requiring an explicit CREATE,  
I've already encountered usecases where this makes things very  
annoying, e.g. I'd like to:

INSERT {
   GRAPH ?s { ?s ?p ?o }
}
WHERE {
   ?s a :Thing .
   ?s ?p ?o .
}

4store would require some work to detect new graph URIs being used,  
and explicitly create a graph, but I think it's worth it to avoid  
annoying users.

N.B. it's not necessary to detect removing the last triple from a  
graph, as that doesn't necessarily have to explicitly remove the graph.

- Steve

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Received on Friday, 8 January 2010 11:10:08 GMT

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