CODEWITHSUNDEEP
mysql
Nore
Nore

Reputation:

Truncate all tables (most of which have constraints). How to temporarily drop them

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

Upvotes: 13

Views: 7230

Answers (4)

Berto
Berto

Reputation: 722

Here's what I do from the command prompt:

 mysql -Nse 'show tables' DATABASE_NAME | while read table; do mysql -e "SET FOREIGN_KEY_CHECKS = 0; TRUNCATE table $table" DATABASE_NAME; done

Problem is, if you require authentication, you will need to add a -u YOUR_USERNAME -pYOURPASSWORD after both mysql commands.

If you don't want to enter your password at the command prompt (I don't ever), then you'll need to copy and paste the password after every prompt, which may be several times depending on the number of tables.

Upvotes: 0

Pascal Thivent
Pascal Thivent

Reputation: 570545

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.

Upvotes: 29

user179161
user179161

Reputation: 61

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.

Upvotes: 0

Alexey Sviridov
Alexey Sviridov

Reputation: 3510

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.

Upvotes: 0

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