Question

I need to add INET_ATON to ip field before insert

INSERT INTO (`id`,`ip`) VALUES (NULL,'127.0.0.1');

I need the database to convert ip transparently before insert.
and in select convert it back with INET_NTOA()

I can not change the query to use

INSERT INTO (`id`,`ip`) VALUES (NULL,INET_ATON('127.0.0.1'));

because i have no control over the software that executes those queries

Answer 1

For the insert part you can setup a TRIGGER BEFORE INSERT in the database:

DELIMITER |
DROP TRIGGER IF EXISTS `before_insert_ip`|
CREATE TRIGGER `before_insert_ip` BEFORE INSERT ON `table_name`
FOR EACH ROW
BEGIN
  SET NEW.`ip` = INET_ATON(NEW.`ip`);
END;
|
delimiter;

The SELECT part is a bit more tricky. There is no AFTER SELECT trigger in mysql which you could use to convert the IP back on the way into the application code.

Instead, you could RENAME the real table and hide it behind a VIEW:

RENAME TABLE `table_name` TO `table_name_real`;

CREATE OR REPLACE VIEW `table_name` (`id`, `ip`) AS
  SELECT `id`, INET_NTOA(`ip`) AS `ip` FROM `table_name_real`;

Note: when you use this VIEW, you need to modify the TRIGGER for the INSERT part to use table_name_real instead of table_name