Take a look at http://dev.mysql.com/doc/refman/5.0/en/innodb-foreign-key-constraints.ht ml
"CASCADE: Delete or update the row from the parent table and automatically delete or update the matching rows in the child table. Both ON DELETE CASCADE and ON UPDATE CASCADE are supported. Between two tables, you should not define several ON UPDATE CASCADE clauses that act on the same column in the parent table or in the child table." -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: 20 February 2008 12:44 To: mysql@lists.mysql.com Subject: sql help: delete row where only related to one other row Say I have two tables: table_a ---------- a_id (primary key) b_id table_b ---------- b_id (primary key) name there is a one to many mapping between rows in table b and rows in table a. Say I had an Id of a row in table a an (a_id, say 5). Now, what I want to do is delete the row in table_a (easy enough), but I also want to delete the related row in table_b, if it is ONLY related to the a_id of 5. In other words, I want to delete the row from table b, but I don't want to delete a row from table b that is in use by another row in table a. I'm thinking some type of subquery could do this, but I'm not sure. Can some one tell me how to do this? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
