Rails: Adding an index after adding column

ruby-on-rails indexing migration
user1611830 picture user1611830 · Apr 8, 2013 · Viewed 107.6k times · Source

Suppose I created a table table in a Rails app. Some time later, I add a column running:

rails generate migration AddUser_idColumnToTable user_id:string.

Then I realize I need to add user_id as an index. I know about the add_index method, but where should this method be called? Am I supposed to run a migration (if yes, which one ?), then adding by hand this method?

Answer

Jaap Haagmans picture Jaap Haagmans · Apr 8, 2013

You can run another migration, just for the index:

class AddIndexToTable < ActiveRecord::Migration
  def change
    add_index :table, :user_id
  end
end

Related questions

Index on multiple columns in Ruby on Rails

I'm implementing functionality to track which articles a user has read. create_table "article", :force => true do |t| t.string "title" t.text "content" end This is my migration so far: create_table :user_views do |t| t.integer :…

Read More
Rails: How to add add_index to existing table

I already migrated a table called units with several columns. I was wondering how to migrate in a stand alone 'add_index' to this table using the cmd. Is this code correct: class AddIndexToUnits < ActiveRecord::Migration def self.up …

Read More
Changing Index Page - Ruby on Rails

I am new to rails so go easy. I have developed my blog and deployed it successfully. The entire app is based out of the post_controller. I am wondering how I can reroute the users path to default to …

Read More