Question

I am very new to Triggers and so this is a very beginner question. I am trying simply to, before a row updates, store its id, old and new values, and the current date into a new table. I have tried the following:

DELIMITER //
    DROP TRIGGER IF EXISTS stockTrig//
    CREATE TRIGGER stockTrig BEFORE UPDATE ON products
        FOR EACH ROW
        BEGIN
            IF NEW.quantity != OLD.quantity THEN
                INSERT INTO stock_log SET p_id = OLD.id, old_stock = OLD.quantity, new_stock = NEW.quantity, date = CURDATE();
            END IF;
        END//
DELIMITER;

I’m getting the following:

1235 – This version of MySQL doesn’t yet support ‘multiple triggers with the same action time and event for one table’

…which I don’t quite understand. I am using MySQL 5.1.53, which shouldn’t be outdated. What exactly is going wrong here?

Answer 1

There’s nothing wrong I can see with your code.

Can you just use mysql command line? (like every other dev/DBA I know uses for schema changes?)

Edit:

Your INSERT syntax is unorthodox, but valid for mysql. Normally it would be:

...
INSERT INTO stock_log (p_id, old_stock, new_stock, date)
    VALUES (OLD.id, OLD.quantity, NEW.quantity, CURDATE());
...