Originally found here: http://www.stetsenko.net/2008/10/mysql-how-to-ignore-checking-of-foreign-key-constraints-for-innodb-tables/

Making a note of it here because it always take me a while to find the above article.

You can switch off checking of foreign keys while you truncate/populate the tables in a MySQL database with:

SET FOREIGN_KEY_CHECKS = 0;

and re-enable it with:

SET FOREIGN_KEY_CHECKS = 1;

This is especially useful if, like me, you use an SQL script to pre-populate a MySQL database:

USE `database_name`;
 
SET FOREIGN_KEY_CHECKS = 0;
 
TRUNCATE `table_1`;
TRUNCATE `table_2`;
TRUNCATE `table_3`;
TRUNCATE `table_4`;
 
INSERT INTO `table_1` ...;
INSERT INTO `table_2` ...;
INSERT INTO `table_3` ...;
INSERT INTO `table_4` ...;
 
SET FOREIGN_KEY_CHECKS = 0;