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Re: SPARQL Update feature

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Tue, 13 Jul 2010 14:39:01 +0100
Message-ID: <4C3C6C75.7080905@talis.com>
To: Steve Harris <steve.harris@garlik.com>
CC: Alexandre Passant <alexandre.passant@deri.org>, SPARQL Working Group <public-rdf-dawg@w3.org>

On 13/07/2010 1:25 PM, Steve Harris wrote:
> On 2010-07-13, at 11:46, Alexandre Passant wrote:
> [ snip, all looks good to me ]
>> We initially thought that ALL includes also the default graph, but that will be a problem for removing all named graphs but not the default one (not sure that will happen so often, yet)
>> So better to have ALL = all named graphs, which leads to the following to clean the store
>> or
>> What do you think ?
> I prefer DROP/CLEAR ALL does everything, including the default graph. "ALL" implies that to me.

I'm comfortable with that.

Another possibility for completeness: a special form like


that then puts it outside the issue of whether ALL is all named graphs 
or all graphs.

> If I really want to leave the named graph, and CLEAR the others I can do that with:
> DELETE WHERE { GRAPH ?g { ?x ?y ?z } }
> Admittedly there's no DROP equivalent, for graphs that don't do empty graph culling, but that's well into corner cases AFAIC.

It's not a corner case for me - some implementations are quite happy 
with empty graphs and they don't naturally get culled.  Such grah stores 
are a collection of graphs, not stored in a common quad table.

> Otherwise, you could add a "GRAPH *" like syntax, meaning all named graphs, but I predict that users would confuse GRAPH * and ALL a lot.

Maybe - I'm more comfortable with DROP GRAPH *. With an explicit use of 
GRAPH, and DEFAULT (not GRAPH DEAFULT) it makes sense and is 
explainable.  At least "DROP GRAPH *" does not destroy data that the 
user didn't want addressed.


> - Steve
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Received on Tuesday, 13 July 2010 13:39:41 UTC

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