public function update_type($id, $type, $desc) {
		$sql = "UPDATE cswal_token_type_table SET token_type=:type, 
			token_desc=:desc WHERE token_type_id=:id";
		$params = array(
			'id'	=> $id,
			'type'	=> $type,
			'desc'	=> $desc,
		);
		
		try {
			$retval = $this->db->run_update($sql, $params);
		} catch (Exception $ex) {
			throw new Exception(__METHOD__ .": failed to update type::: ". $ex->getMessage());
		}
		
		return $retval;
	}