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?