Re: CONSTRUCT an RDF Datest

On 29/11/15 01:45, Tara Athan wrote:
> Update: In a private reply, someone mentioned that it is possible to
> create and update named graphs in a Graph Store, e.g. with the SPARQL
> Update language. However, in my usecase, I am only interested in
> creating an immutable RDF Dataset, not a mutable Graph Store. This hint
> was useful in letting me see what a CONSTRUCT for an RDF Dataset might
> look like, though (patterned after INSERT).
>
> For example, suppose I want to filter an RDF Dataset to extract a new
> dataset where only named graphs having a metadata triple in the default
> graph matching a certain filter are retained. It might be expressed so:
>
> CONSTRUCT
>   { ?name ex:observedAt ?date
>    GRAPH ?name
>     { ?s ?p ?o}
> }
> WHERE
>   {
>    { ?name ex:observedAt ?date }
>    GRAPH ?name
>        {?s ?p ?o}
>    FILTER (?date > 2015-06-01)
> }

In this particular example, do the results need to exactly conform to 
the structure of the dataset?  If the ex:observedAt is put in the 
results in the same graph:

CONSTRUCT
   { ?name ex:observedAt ?date
     ?s ?p ?o
}
WHERE ...

>
> Is there any theoretical or technical obstacle to this?

There's no obstacle.  A Google Summer of Code project added this to 
Apache Jena this year and it'll be in the next release.

It follows the design you gave:

https://jena.apache.org/documentation/query/construct-quad.html

 Andy

>
> Tara
>

Received on Sunday, 29 November 2015 10:33:33 UTC