Rails DB Migration - How To Drop a Table?

You won't always be able to simply generate the migration to already have the code you want. You can create an empty migration and then populate it with the code you need.

You can find information about how to accomplish different tasks in a migration here:

http://api.rubyonrails.org/classes/ActiveRecord/Migration.html

More specifically, you can see how to drop a table using the following approach:

drop_table :table_name

First generate an empty migration with any name you'd like. It's important to do it this way since it creates the appropriate date.

rails generate migration DropProductsTable

This will generate a .rb file in /db/migrate/ like 20111015185025_drop_products_table.rb

Now edit that file to look like this:

class DropProductsTable < ActiveRecord::Migration
  def up
    drop_table :products
  end

  def down
    raise ActiveRecord::IrreversibleMigration
  end
end

The only thing I added was drop_table :products and raise ActiveRecord::IrreversibleMigration.

Then run rake db:migrate and it'll drop the table for you.

Write your migration manually. E.g. run rails g migration DropUsers.

As for the code of the migration I'm just gonna quote Maxwell Holder's post Rails Migration Checklist

BAD - running rake db:migrate and then rake db:rollback will fail

class DropUsers < ActiveRecord::Migration
  def change
    drop_table :users
  end
end

GOOD - reveals intent that migration should not be reversible

class DropUsers < ActiveRecord::Migration
  def up
    drop_table :users
  end

  def down
    fail ActiveRecord::IrreversibleMigration
  end
end

BETTER - is actually reversible

class DropUsers < ActiveRecord::Migration
  def change
    drop_table :users do |t|
      t.string :email, null: false
      t.timestamps null: false
    end
  end
end

Warning: Do this at your own risk, as @z-atef and @nzifnab correctly point out, Rails will not be aware of these changes, your migration sequence fill fail and your schema will be different from your coworkers'. This is meant as a resource for locally tinkering with development only.

While the answers provided here work properly, I wanted something a bit more 'straightforward', I found it here: link First enter rails console:

$rails console

Then just type:

ActiveRecord::Migration.drop_table(:table_name)

And done, worked for me!