Using ActiveRecord outside Rails

ActiveRecord is a nice lightweight way to access database tables from Ruby code. I use it outside of Rails for simple scripts and in customer test scripts.

If you want to use ActiveRecord outside of Rails you just need to:
- Download ActiveRecord
- Configure the database
- Define the schema
That's it!

Download ActiveRecord

gem install activerecord

Configure the database

database_configuration.rb

require 'rubygems'
require 'active_record'

ActiveRecord::Base.establish_connection(
  :adapter => "mysql",
  :host => "localhost",
  :database => "appdb",
  :username => "appuser",
  :password => "secret"
)

Define the Schema

schema.rb

require 'database_configuration'

class Project < ActiveRecord::Base
end

class User < ActiveRecord::Base
end

class Comment < ActiveRecord::Base
end

We can now use our ActiveRecord database objects in our scripts.

script.rb

require 'schema'

user = User.find_by_username("craig@facedowndog.com")
puts user.id

comment = Comment.find_by_user_id(user.id)
puts comment.comment

projects = Project.find(:all)
puts projects.length.to_s + " projects"