Re: paper on recursive SPARQL at ISWC

Peter,

At TopQuadrant, we have used recursive queries with SPIN functions and with magic properties. 

Here is an example of a recursive SPARQL query done with magic graphs. It returns all SPOs that are on a given resource and any of the object resources it references.

It is called as simply as this:

SELECT *
WHERE {
    (ns:Subject) sn:getSubGraph (?s ?p ?o)
}

sn:getSubGraph (spin:MagicProperty)

Flatten subgraph is a magic properrty that returns rdf statements (?s ?p ?o) for a node and all its object nodes recursively. The recursion excludes nodes at the range end of rdf:type properties.

Arguments

sp:arg1 (rdfs:Resource): 
Function body

SELECT ?s ?p ?o
WHERE {
    {
        {
            ?arg1 ?p1 ?o1 .
            FILTER bound(?arg1) .
            FILTER (?p1 != rdf:type) .
        } .
        ( ?o1 ) sn:getSubGraph ( ?s ?p ?o ) .
    }
    UNION
    {
        ?arg1 ?p ?o .
        BIND (?arg1 AS ?s) .
    } .
}

A call 

Ralph
rhodgson@topquadrant.com




> On Oct 14, 2015, at 6:49 PM, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote:
> 
> There was a paper presented at ISWC on recursive SPARQL.
> 
> Juan L. Reutter, Adrian Soto and Domagoj Vrgoc
> Recursion in SPARQL
> iswc2015.semanticweb.org/sites/iswc2015.semanticweb.org/files/93660017.pdf
> 
> Some of the information in this paper might be relevant to SHACL.
> 
> 
> peter
>