Writing a Ruby on Rails application without using a database

Some of you may be wondering “why would you want to use Rails without a database?” There are several situations why a database would not be needed, and I’ve run into quite a few of them. One of the specific cases was when I wanted to write a web interface for an application that only had a REST interface available to the public.

If you find yourself needing to write a Rails application without a database, just do the following:

For Rails 1.0 and up:

config/environment.rb:

config.frameworks -= [ :active_record ]

test/test_helper.rb

class Test::Unit::TestCase
  self.use_transactional_fixtures = false
  self.use_instantiated_fixtures  = false
  def load_fixtures
  end
end

For Rails 2.1 and up: Comment out both of the lines that begin with ActiveRecord::Base in config/initializers/new_rails_defaults.rb:

if defined?(ActiveRecord)
  # Include Active Record class name as root for JSON serialized output.
  # ActiveRecord::Base.include_root_in_json = true

  # Store the full class name (including module namespace) in STI type column.
  # ActiveRecord::Base.store_full_sti_class = true
end

For more details, review the full article on rubyonrails.org.