Re: DISTINCT in sparql definitions

On 10/24/2015 11:01, Vladimir Alexiev wrote:
> http://w3c.github.io/data-shapes/shacl/#PropertyScope has this SPARQL
> DEFINITION:
>
> SELECT DISTINCT ?this
> WHERE {
> 	?this $predicate ?any .
> }
>
> (in total , DISTINCT occurs 7 times in the document)
>
> A problem I see is that if the result of this query is very large, doing the
> DISTINCT is expensive.
> A more economic query would use
>
>     FILTER EXISTS {?this $predicate ?any}.
>
> But afaik, you can't make a query out of a FILTER only...

Exactly this is the problem. FILTERs would not bind new values, but here 
we need to produce such bindings.

Holger

Received on Saturday, 24 October 2015 03:27:27 UTC