let q1 = "select att0 from namespace where att1='http://www.cs.unibo.it/helm/schemas/mattone.rdf#'" in
let ns = pgresult_to_string (c#exec q1) in
let q2 = ("select att0 from property where att2='" ^ p ^ "' and att1=" ^ ns) in
let retval = pgresult_to_string (c#exec q2) in
let q1 = "select att0 from namespace where att1='http://www.cs.unibo.it/helm/schemas/mattone.rdf#'" in
let ns = pgresult_to_string (c#exec q1) in
let q2 = ("select att0 from property where att2='" ^ p ^ "' and att1=" ^ ns) in
let retval = pgresult_to_string (c#exec q2) in