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Re: [limit per resource] implementation experience and/or concerns?

From: Alexandre Passant <alexandre.passant@deri.org>
Date: Fri, 17 Apr 2009 13:40:41 +0100
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <E5E1A84D-A630-487E-989B-FE6C9381C2CA@deri.org>
To: Lee Feigenbaum <lee@thefigtrees.net>
Hi,

Le 17 avr. 09 à 05:34, Lee Feigenbaum a écrit :

> (just looking to get a bit of background discussion in advance of  
> tuesday, to save time on the teleconference)
>
> http://www.w3.org/2009/sparql/wiki/Feature:LimitPerResource
>
> LIMIT, in SPARQL, normally just limits the total number of results  
> returned. Combined with DISTINCT, it limits the total number of  
> distinct tuples returned. Combined with an aggregate/grouping  
> extension, it can limit the total number of groups returned.
>
> But there's no way to limit based on certain variable(s) while  
> allowing multiple rows per limiting variable. That's what limit per  
> resource is about.
>
> The wiki page has some good use cases.
>
> I must say: while this is a problem I have come up against  
> personally in the past, this is not a proposed solution that I was  
> familiar with. Which is my main concern: while this seems like a  
> fairly straightforward extension to SPARQL, it's not implemented  
> anywhere that I know of.

The syntax defined in the wiki page was just a proposal, as I'm  
neither aware of any implementations.

>
>
> So a few questions:
>
> 1/ does anyone implement this in SPARQL?
>
> 2/ does anyone implement this elsewhere (e.g. in SQL)?
>
> 3/ on the surface, are there any implementation, specification, or  
> other concerns about this feature?

As I wrote in the uses cases, I think that's particularly needed when  
writing 'resource-oriented' queries.

I'd be happy as well if it can be covered by another feature, such as  
subselect.

Alex.

>
>
>
> Lee
>
>

-- 
Alexandre Passant
Digital Enterprise Research Institute
National University of Ireland, Galway
:me owl:sameAs <http://apassant.net/alex> .
Received on Friday, 17 April 2009 12:41:25 GMT

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