Ruby on Rails: How can I revert a migration with rake db:migrate?

Run the following command

rake db:migrate:down VERSION=<version>

where <version> is the version number of your migration file you want to revert.

eg. if you want to revert a migration with file name 3846656238_create_users.rb

rake db:migrate:down VERSION=3846656238

Just run this command:

rake db:rollback

I believe there are three options available for reverting migrations (they also overlap):

1. Roll down the most recent migration:

   rake db:migrate:down # Rails 2 only.

2. Roll down a number(n) of recent migrations:

   rake db:rollback STEP=n

3. Roll down to a previous, specific version:

   $ rake db:migrate:down VERSION=nnn # Rails 3 (provide version number also).

Version Number means the SHA(Secure Hash Algorithm) for the commit which is a long hexadecimal number which looks something like 886af3194768917c78e... You can see it by doing git log

You can see these commands (and others) with their descriptions by using rake -T db: which for rails 3.2 includes:

rake db:migrate         # Migrate the database (options: VERSION=x, VERBOSE=false)
rake db:migrate:status  # Display status of migrations
rake db:rollback        # Rolls the schema back to the previous version (specify steps w/ STEP=n)