Question

Is there a nice easy way to drop all tables from a MySQL database, ignoring any foreign key constraints that may be in there?

Answer 1

I found the generated set of drop statements useful, and recommend these tweaks:

1. Limit the generated drops to your database like this:

SELECT concat('DROP TABLE IF EXISTS `', table_name, '`;')
FROM information_schema.tables
WHERE table_schema = 'MyDatabaseName';

Note 1: This does not execute the DROP statements, it just gives you a list of them. You will need to cut and paste the output into your SQL engine to execute them.

Note 2: If you have VIEWs, you’ll have to correct each DROP TABLE `VIEW_NAME` statement to DROP VIEW `VIEW_NAME` manually.

2. Note, per http://dev.mysql.com/doc/refman/5.5/en/drop-table.html, dropping with cascade is pointless / misleading:

“RESTRICT and CASCADE are permitted to make porting easier. In MySQL 5.5, they do nothing.”

Therefore, in order for the drop statements to work if you need:

SET FOREIGN_KEY_CHECKS = 0

This will disable referential integrity checks – so when you are done performing the drops you need, you will want to reset key checking with

SET FOREIGN_KEY_CHECKS = 1

3. The final execution should look like:

SET FOREIGN_KEY_CHECKS = 0;
-- Your semicolon separated list of DROP statements here
SET FOREIGN_KEY_CHECKS = 1;

NB: to use output of SELECT easier, mysql -B option can help.