• 8.2 Script the upgrade and downgrade of a database
  • Learning Objectives
  • Apply database changes

8.2 Script the upgrade and downgrade of a database

Learning Objectives

By the end of this lesson you will be able to:

• Upgrade and downgrade the database through a script.

Apply database changes

1. Rollback changes that were previously applied to a database.

   cd /var/www/rails

   sudo rake db:rollback

2. The example below is part of the sample application for Ruby on Rails Tutorial: Learn Rails by Example by Michael Hartl. You can also define the database schema in a script.

   “`

   class CreateUsers < ActiveRecord::Migration def self.up create_table :users do |t| t.string :name t.string :email

   t.timestamps
   

   end end

   def self.down drop_table :users end end

   “`

3. The example below is using a tool called Liquibase for database change management.

   “`

   “`