ActiveRecord Stand-alone migrations

gem install active_record_migrations -v


ActiveRecord Stand-alone Migrations

Allows you to use ActiveRecord migrations in non-Rails projects.


Add this line to your application's Gemfile (run bundle init if you don't have one):

gem 'active_record_migrations'
gem 'sqlite3' # or 'pg', 'mysql2', ...

And then execute:

$ bundle --binstubs

Create a Rakefile:

require 'active_record_migrations'


By default, your database configurations will be read from db/config.yml and your migration files will be created under db/migrate. If you want to keep with the defaults, create your db/config.yml:

      adapter: postgresql
      database: my_db
      encoding: utf8
      host: localhost
      port: 5432
      username: noel
      password: s3cret
      adapter: sqlite3
      database: db/test.sqlite3
      pool: 5
      timeout: 5000

If you prefer to specify your settings in plain Ruby, add this to your Rakefile, before calling ActiveRecordMigrations.load_tasks:

ActiveRecordMigrations.configure do |c|
  c.database_configuration = {
    'development' => {'adapter' => 'sqlite3', 'database' => 'db/custom.sqlite3'},
  # Other settings:
  c.schema_format = :sql # default is :ruby
  # c.yaml_config = 'db/config.yml'
  # c.environment = ENV['db']
  # c.db_dir = 'db'
  # c.migrations_paths = ['db/migrate'] # the first entry will be used by the generator

Take a look at the Migrations Guide for more details.

The main difference is that instead of rails generate migration (or rails g migration), the generator is implemented as a Rake task. So you should use it like rake "db:new_migration[CreateUser, name birth:date]" (double quotes are required if you use this form). Alternatively you could run it as rake db:new_migration name=CreateUser options="name birth:date".

Just run rake db:new_migration for help on usage.

You can specify the environment by setting the db environment variable:

rake db:migrate db=production


From ActiveRecord 5.0.2 and above you should use v5.0.2.1 or above. That version isn't locked to ActiveRecord 5.0.2 as in previous versions, which means it should work fine with any ActiveRecord version starting with 5.0.2.

Up to ActiveRecord 5.0.1 we relied on overriding a method in the migration generator to support custom paths for the migrations, so the version used to follow ActiveRecord versions plus a patch version from our own. For instance, if AR version is 4.0.1, this gem would be versioned 4.0.1.x with x starting in 0.

I can't find a release for the AR version we rely on

We had to use pessimistic versioning up to because we relied on internal details of AR migrations in order to override the migrations path. The optimistic branch should work with any previous version since ActiveRecord 4.0.0.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request