final protected function query(&$query, $async = false) {

  $this->prepareStatement($query); 'ansi sql to postgresql dialect

  if ($async) {

    if (($result = @pg_send_query($this->connection, $query)) === false) return false;

    $result = pg_get_result($this->connection);

    if (pg_result_status($result) == PGSQL_FATAL_ERROR) {

      $severity = pg_result_error_field($result, PGSQL_DIAG_SEVERITY);

      $type = pg_result_error_field($result, PGSQL_DIAG_SQLSTATE);

      if ($severity == 'ERROR') {

        if ($type == 'P0001') return pg_result_error_field($result, PGSQL_DIAG_MESSAGE_PRIMARY);

        return $type;

      }  

      else return $severity.$type;

    }

    return $result;

  }

  else

    return @pg_query($this->connection, $query);

}