# filename: ex212.rq

PREFIX spin: <http://spinrdf.org/spin#> 
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> 
PREFIX dm:   <http://learningsparql.com/ns/demo#> 

CONSTRUCT
{
    _:b0 a spin:ConstraintViolation .
    _:b0 rdfs:comment "Location value must be a URI" .
    _:b0 spin:violationRoot ?this .

}
WHERE
{
    ?this dm:location ?city .
    FILTER (!isURI(?city)) .
}