Anıl Özselgin ozselgin
jeremyjarrell
/ Idempotent migration in MySQL example
Created
July 25, 2013 20:06
In MySQL, IF statements cannot exist outside of stored procedures. Therefore, to create an idempotent migration for MySQL it's necessary to wrap the migration in a stored procedure and execute that stored procedure against the database to perform the migration.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| DELIMITER $$ | |
| DROP PROCEDURE IF EXISTS add_email_address_column_to_customers_table $$ | |
| -- Create the stored procedure to perform the migration | |
| CREATE PROCEDURE add_email_address_column_to_customers_table() | |
| BEGIN | |
| -- Add the email_address column to the customers table, if it doesn't already exist |