truncate all tables (most of which have constraints). How to temoprarily drop them

Question

I have a development database (MYSQL) which I would like to load with fresh data at some point. I would like to delete the content of all tables. What is the best way, as automated as possible, to delete the content of all tables (including those that have foreign key constraints). Is there a truncate all/ drop all equivalent constraints?

Thanks

Answer 1

If you want truncate REALLY all tables better way i'm think drop and create database with previously extracted database schema. Or you just can two copy of same database - test and empty. After filling your tables, just delete test db and copy empty to test.

Answer 2

TRUNCATE (TABLE) tbl_name will truncate a single table. You can stick that in a script and loop through it with all of your table names.

http://dev.mysql.com/doc/refman/5.0/en/truncate.html

You may want to look into migrations, too, but I think Alexey has the right approach there. It's very similar to how RoR handles rebuilding the test database on each run.

Answer 3

I think you can do the following:

1. Disable the foreign key constraint check

   mysql> SET FOREIGN_KEY_CHECKS = 0;
   

2. Truncate your tables

   mysql> TRUNCATE MY_TABLE;
   

3. Enable the foreign key constraint check

   mysql> SET FOREIGN_KEY_CHECKS = 1;
   

I prefer disabling the foreign key constraints temporarily to dropping/recreating them.