Search code examples
sparqltriplestorestardog

Stardog rule doesn't trigger

I'm having trouble writing a correct Stardog rule. As I haven't found a way to validate the syntax of the rule, I don't now if it's a syntax or a logical error. Eitherway, the rule doesn't seem to be triggered when reasoning is enabled (reasoning=SL in version 2, reasoning=true in version 3).

@prefix : <http://www.example.org/rules#> .
@prefix rule: <tag:stardog:api:rule:> .
@base <http://www.example.org/rules#> .

[] a rule:SPARQLRule ;
  rule:content """
PREFIX : <http://www.example.org/rules#>
PREFIX draft: <http://our/prefix#>
IF {
    ?x a draft:Obs; draft:has_code ?code .
    ?z a <http://www.w3.org/ns/sparql#UUID> . // OR: BIND (UUID() AS ?z)
   }
THEN {
    ?z a draft:Code .
    ?x draft:has_code ?z .
}
""" .

I'm trying to trigger the rule with the following SPARQL query:

PREFIX : <http://our/prefix>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT ?code
FROM <tag:stardog:api:context:default> 
FROM <http://our/graph> 
WHERE {
    ?s rdf:type :Obs .
    ?obs :has_code ?code .
}
Solution

  • This is likely due to the cyclic nature of the rule. You're inferring :has_code which will in turn be used to fire the rule again, and again, and so forth.

    This is a bit easier to visualize when you consider how rules with more than one atom in the header a broken up.