Add a default value to a column through a migration

Question

How do I add a default value to a column that already exists through a migration?

All the documentation I can find shows you how to do it if the column doesn\'t alr

Answer 1

Execute:

rails generate migration add_column_to_table column:boolean

It will generate this migration:

class AddColumnToTable < ActiveRecord::Migration
  def change
    add_column :table, :column, :boolean
  end
end

Set the default value adding :default => 1

add_column :table, :column, :boolean, :default => 1

Run:

rake db:migrate