code: static void setSingleParam(String key, String value, DbConn cnx)
      {
          QueryResult r = cnx.runUpdate("globalprm_update_value_by_key", value, key);
          if (r.nbUpdated == 0)
          {
              cnx.runUpdate("globalprm_insert", key, value);
          }
          cnx.commit();
      }
docs: Checks if a parameter exists. If it exists, it is updated. If it doesn't, it is created. Only works for parameters which key is
  unique. Will create a transaction on the given entity manager.