TRIGGER BEFORE INSERT - ALTER ADD column form insert value

[Mihai Grososiu]

Hello,
I'm stuck with this problem:
Before insert on user_types table, I have to create a column in user_rights table and the column name be the `type` inserted value (user_types.type).

DELIMITER $$;
DROP TRIGGER `new_type`$$
CREATE TRIGGER `new_type` BEFORE INSERT on `user_types`
FOR EACH ROW BEGIN
ALTER TABLE `user_rights` ADD NEW.type BINARY( 9 ) NULL;
END$$
DELIMITER ;$$

I've tried with trigger and I receive this error:
Explicit or implicit commit is not allowed in stored function or trigger.