Re: Limiting a query by setting a maximum number of distinct values for a given variable.

Only in SPARQL 1.1. But even there it can be tricky. You can use sub queries with limits in them, but the underpinning logic isn't necessarily what you'd expect - the sub query is executed logically "before" the outer query - so it's still quite tricky. A query to do what you want will be ludicrously verbose. 

In short: it's easier to do it at the application layer. Get all the towns, then do LIMIT 100 queries on each. 

- Steve

Sent on the move.

On 15 Oct 2010, at 21:23, Olivier Rossel <olivier.rossel@gmail.com> wrote:

> Well, let me rephrase a little bit the subject of my mail.
> I want to retrieve a set of towns, their various labels and their geolocation.
> The labels can be in english and/or spanish and/or french and/or deutsch.
> 
> My data set contains a LOT of towns.
> So I will limit my query.
> I plan to retrieve towns data by packs of 100 towns.
> 
> My first idea was to use the SPARQL "LIMIT" and "OFFSET" keywords.
> But I think they work at resultSet's row level, and each row of {town,
> label, longitude, latitude}
> counts for 1.
> 
> So 100 rows of the resultSet do not correspond to data for 100 distinct towns.
> 
> 
> Is there a way to constrain my SPARQL queries to return all the data for the
> first 100 towns, then all the data for the second 100 towns, etc ?
> 
> Note: oh, by the way, in my app, I use CONSTRUCT and SELECT ! I don't know if
> that is an important point. But anyway... :)
> 
> Any help is gladly welcome.
> 
> Thanks.
> 
> --
> Olivier Rossel
>

Received on Saturday, 16 October 2010 06:33:55 UTC