DESCRIBE SPARQL query with virtual graph

Support
1

After being able to successfully reproduce the example with employees and department in the documentation and creating a virtual graph from a MySQL database, I've been able to perform SPARQL queries like simple SELECT but also CONSTRUCT to get all the data about employees, for instance:

PREFIX : <http://api.stardog.com/>
CONSTRUCT { ?s ?p ?o } 
WHERE {
   GRAPH <virtual://sample> {
      ?s a :EMP ;
         ?p ?o .
   }
}

However, I cannot make it work for DESCRIBE queries like:

PREFIX : <http://api.stardog.com/>
DESCRIBE ?s 
WHERE {
   GRAPH <virtual://sample> {
      ?s a :EMP .
   }
}

I'm getting the following error message:

000IA2: com.complexible.stardog.plan.eval.ExecutionException: Unrecognized operator: Describe

Are DESCRIBE queries not supported on virtual graphs?

2

Hi Rogargon,

Unfortunately this is not currently implemented. But perhaps you could try something like:

graph <virtual://...> {
  ?s a :EMP .
  ?s ?p ?p
}
3

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