I wouldn't say I was a newbie at all. I've been coding in PHP, mySQL for like 6 years now. But I just never learned (or maybe had a reason to) why I would use "KEY (a_id, b_id)" rather than "KEY (a_id)" and "KEY (b_id)". Would someone be so kind as to point me at an online tutorial or just explain what the difference is or what the use of "KEY (a_id, b_id)", and does it matter if I reverse them like "KEY (b_id, a_id)"? I mean, I understand that the key will be a hybrid of the two columns, but why would you want that? A friend tried to explain it in the case you have a third table that is what I call a "glue" table, but I still don't see how this works.
CREATE TABLE parent ( par_id INT NOT NULL, PRIMARY KEY (par_id) ) TYPE = INNODB; CREATE TABLE child ( par_id INT NOT NULL, child_id INT NOT NULL, PRIMARY KEY (par_id, child_id), FOREIGN KEY (par_id) REFERENCES parent (par_id) ON DELETE CASCADE ) TYPE = INNODB; Btw, I saw this here: http://165.193.123.40/isapi/product_id~%7B60B19985-0F7B-4E72-88ED-C472616E45 D8%7D/element_id~%7BF31998C7-4725-4997-AB4A-09AC0D03A6B3%7D/st~%7B822202F4-E 865-472D-B32F-BE77D3B7ACE1%7D/content/articlex.asp Which is a great tutorial on mySQL by Paul Dubois. --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
