How to delete migration files in Rails 3

Question

I would like to remove/delete a migration file. How would I go about doing that? I know there are similar questions on here but as an update, is there a better way than doin

Answer 1

Another way to delete the migration:

$ rails d migration SameMigrationNameAsUsedToGenerate

Use it before rake db:migrate is executed because changes in database will stay forever :) - or remove changes in Database manually

Answer 2

Run below commands from app's home directory:

1. rake db:migrate:down VERSION="20140311142212" (here version is the timestamp prepended by rails when migration was created. This action will revert DB changes due to this migration)

2. Run "rails destroy migration migration_name" (migration_name is the one use chose while creating migration. Remove "timestamp_" from your migration file name to get it)

Answer 3

You can also run a down migration like so:

rake db:migrate:down VERSION=versionnumber

Refer to the Ruby on Rails guide on migrations for more info.

Answer 4

This also works in Rails 5.

If the migration was the most recent one you can remove the database column(s) that the migration added by doing:

rake db:rollback

then remove the migration file itself by running:

rails d migration WhateverYourMigrationWasNamed.rb 

Answer 5

None of these answers quite fit the problem i had as the migration i wanted to delete was missing: I had created and run a migration in some other branch, which was then discarded. The problem is when a migration is run, rails adds the version into a schema_migrations table in the database. So even if it isn't listed in your db structure or schema, rails looks for it. You can reveal these orphaned migrations by running:

rails db:migrate:status

Note the versions of the missing migrations and head into the db console:

rails dbconsole

Now remove the versions from the migration table manually:

delete from schema_migrations where version='<version>';

You should now be good.