Oracle限制某个帐号只能在特定机器上访问数据库

CREATE OR REPLACE TRIGGER logon_ip_control
  AFTER logon ON user_test.schema
BEGIN
  IF USER IN ('user_test') THEN
    IF sys_context('USERENV', 'IP_ADDRESS') NOT IN
       ('192.168.1.10', '192.168.1.10') THEN

      raise_application_error(-20001,
                              'You are not allowed to connect to the database');
    END IF;
  END IF;
END;