How to rollback a specific migration? – Dev

The best answers to the question “How to rollback a specific migration?” in the category Dev.

QUESTION:

I have the following migration file db\migrate\20100905201547_create_blocks.rb

How can I specifically rollback that migration file?

ANSWER:

rake db:migrate:down VERSION=20100905201547

will roll back the specific file.


To find the version of all migrations, you can use this command:

rake db:migrate:status

Or, simply the prefix of the migration’s file name is the version you need to rollback.


See the Ruby on Rails guide entry on migrations.

ANSWER:

rake db:rollback STEP=1

Is a way to do this, if the migration you want to rollback is the last one applied. You can substitute 1 for however many migrations you want to go back.

For example:

rake db:rollback STEP=5

Will also rollback all the migration that happened later (4, 3, 2 and also 1).

To roll back all migrations back to (and including) a target migration, use: (This corrected command was added AFTER all the comments pointing out the error in the original post)

rake db:migrate VERSION=20100905201547

In order to rollback ONLY ONE specific migration (OUT OF ORDER) use:

rake db:migrate:down VERSION=20100905201547

Note that this will NOT rollback any interceding migrations — only the one listed. If that is not what you intended, you can safely run rake db:migrate and it will re-run only that one, skipping any others that were not previously rolled back.

And if you ever want to migrate a single migration out of order, there is also its inverse db:migrate:up:

rake db:migrate:up VERSION=20100905201547

ANSWER:

You can rollback your migration by using rake db:rollback with different options. The syntax will be different according to your requirements.

If you want to rollback just the last migration, then you can use either

rake db:rollback

or

rake db:rollback STEP=1

If you want rollback number of migrations at once, then you simply pass an argument:

rake db:rollback STEP=n

where n is number of migrations to rollback, counting from latest migration.

If you want to rollback to a specific migration, then you should pass the version of the migration in the following:

rake db:migrate:down VERSION=xxxxx

where xxxxx is the version number of the migration.

ANSWER:

To rollback the last migration you can do:

rake db:rollback

If you want to rollback a specific migration with a version you should do:

rake db:migrate:down VERSION=YOUR_MIGRATION_VERSION

For e.g. if the version is 20141201122027, you will do:

rake db:migrate:down VERSION=20141201122027

to rollback that specific migration.