let unlink_query = fun query ->
let (queries, to_be_removed) =
List.partition (fun q -> q.qry_name <> q.qry_name)
query.qry_db.db_queries
in
query.qry_db.db_queries <- queries;
match to_be_removed with
| [q] -> q.qry_db <- (Obj.magic 0)
| _ -> Dbf_misc.ie ()