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Re: Shortcuts in Update

From: Lee Feigenbaum <lee@thefigtrees.net>
Date: Sun, 18 Jul 2010 15:53:34 -0400
Message-ID: <4C435BBE.9030302@thefigtrees.net>
To: Alexandre Passant <alexandre.passant@deri.org>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>
On 7/16/2010 1:02 PM, Alexandre Passant wrote:
> Hi,
>
> While we closed ISSUE-24 [1] and allow moving data between graphs [2], I'd like to re-open the discussion on shortcuts for the related commands - started by Steve and Andy [3].
>
> In particular:
>
> 1) Copy data from one graph to another
>
> COPY ( [GRAPH]<g2>  | DEFAULT) INTO ( [GRAPH]<g1>  | DEFAULT)
>
> shortcut for
>
> DROP SILENT (GRAPH<g1>  | DEFAULT)
> INSERT { ( GRAPH<g1>  | DEFAULT) { ?s ?p ?o } } WHERE { ( GRAPH<g2>  | DEFAULT) { ?s ?p ?o } }
>
> 2) Move data from one graph to another
>
> MOVE ( [GRAPH]<g2>  | DEFAULT) INTO ( [GRAPH]<g1>  | DEFAULT)
>
> shortcut for
>
> DROP SILENT ( GRAPH<g1>  | DEFAULT)
> INSERT { (GRAPH<g1>  | DEFAULT) { ?s ?p ?o } } WHERE { (GRAPH<g2>  | DEFAULT) { ?s ?p ?o } }
> DROP ( GRAPH<g2>  | DEFAULT)
>
> 2) Add data from one graph to another
>
> ADD ( [GRAPH]<g2>  | DEFAULT) INTO ( [GRAPH]<g1>  | DEFAULT)
>
> shortcut for
>
> INSERT { (GRAPH<g1>  | DEFAULT) { ?s ?p ?o } } WHERE { (GRAPH<g2>  | DEFAULT)  { ?s ?p ?o } }
>
> Previous concerns by Andy and Steve where about "attempting to define syntactic shortcuts in a language that's not in widespread use yet".
> Yet, I find that these command could reduce the burden of some useful patterns, e.g. when having temporary graphs and then moving their data into "permanent graphs".
> Might be relevant when dealing with temporal information (blogs, sensors, etc.) that needs to be processed / validated before being considered stable enough.
>
> I'd like to start the discussion here and follow-up on a next t-con (27th, I'm not available next week) depending on how it goes.

FWIW, I strongly share the concerns quoted above. I think it's a bad 
idea to define shortcuts for language that doesn't exist yet. Once 
SPARQL Update is a Rec and people begin using it, implementors will 
receive feedback from users and begin implementing new syntactic forms 
where needed, and these can be standardized the next time around. I fear 
that including these sorts of shortcuts at this point raises the 
learning curve and overall complexity of the language without having any 
empirical evidence to go by that their value outweighs their cost.

Lee

>
> Alex.
>
> [1] http://www.w3.org/2009/sparql/track/issues/24
> [2] http://www.w3.org/2009/sparql/meeting/2010-01-12#resolution_8
> [3] http://lists.w3.org/Archives/Public/public-rdf-dawg/2009OctDec/0676.html
>
> --
> Dr. Alexandre Passant
> Digital Enterprise Research Institute
> National University of Ireland, Galway
> :me owl:sameAs<http://apassant.net/alex>  .
>
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Received on Sunday, 18 July 2010 19:54:14 GMT

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