How to remove the cancelled migration from the db folder - ruby-on-rails

Question

I want to remove a migration from my application.
I have a migration file 20141105030942_removedate_fromexpense.rb
the class file for the migrations is
class RemovedateFromexpense < ActiveRecord::Migration
def change
remove_column :expenses, :date, :date
end
end
When I give this command:
rake db:migrate:down VERSION=20141105030942
I get the following error:
== 20141105030942 RemovedateFromexpense: reverting ============================
-- add_column(:expenses, :date, :date)
rake aborted!
StandardError: An error has occurred, this migration was canceled:
SQLite3::SQLException: duplicate column name: date: ALTER TABLE "expenses" ADD "date" date/home/sumyvps/.rvm/gems/ruby-1.9.3-p545#railstutorial_rails_4_0/gems/sqlite3-1.3.8/lib/sqlite3/database.rb:91:in `initialize'
db:migrate:status for migration file is as below
up 20141105030942 Removedate fromexpense
Has anyone an idea why this is happening?

Answer 1

You do not need to specify the column type in your migration file. Just the name of the table and the column is enough to remove the column from the table.
Edit your migration file to:
class RemovedateFromexpense < ActiveRecord::Migration
def change
remove_column :expenses, :date
end
end
And then run:
rake db:migrate
This should do the work.

Answer 2

A common task is to rollback the last migration. For example, if you made a mistake in it and wish to correct it. Rather than tracking down the version number associated with the previous migration you can run:
rake db:rollback
This will rollback the latest migration, either by reverting the change method or by running the down method. If you need to undo several migrations you can provide a STEP parameter:
rake db:rollback STEP=3
will revert the last 3 migrations.
First Run:
rails generate migration RemoveDateFromExpense date:date
then rake db:migrate
Hope this help!