using ActiveRecord without Rails

ActiveRecord_without_Rails.md

There are plenty of tips out there for using ActiveRecord without Rails, but I was having trouble synthesizing all of the relevant information. Once I got things working, I decided to bring together all of the important pieces I used.

Steps, for an imaginary app called MyApp:

1. Make directories

    mkdir myapp
    mkdir myapp/lib
    mkdir myapp/db
    mkdir myapp/config
   

2. Create Gemfile

• bundle init
• edit accordingly, making sure to include the gems listed in the Gemfile
• bundle install

3. Create Rakefile as shown below
4. Create your database

• rake db:create

5. Create your migration(s) using the syntax described here

    rake db:new_migration name=CreateUsers options="attr_1:type attr_2:type attr_3:type"
    rake db:migrate
   

6. Create your models

• touch lib/models/<model_name>.rb
• be sure to inherit from ActiveRecord, e.g. class User < ActiveRecord::Base

7. Make sure to require the environment.rb file in whatever script you initiate
8. You're good to go!

Sources:

• Blog post by Dan Friedman
• ActiveRecord Migrations gem

config.yml

# default source for active_record_migrations. put this in <app_root>/db/

development:
  adapter:  sqlite3
  database: db/development.sqlite3
  timeout:  5000

test:
  adapter:  sqlite3
  database: db/test.sqlite3
  timeout:  5000

environment.rb

# configures app environment. put this in <app_root>/config/
# your app should require this file before any other code, so
# require it on the first line of the first script that runs.

require 'bundler/setup'
require 'yaml'
require 'active_record'

# assumes config file is in <app_root>/db/config.yml, as required by active_record_migrations
db_config = YAML.load_file( 'db/config.yml' )[ <your_app_env> ]
ActiveRecord::Base.establish_connection( db_config )

# load all models, assuming they're in <app_root>/lib/models
Dir.glob( 'lib/*' ).each do |folder|
  Dir.glob( folder + '/*.rb' ).each do |file|
  require_relative "../#{file}"
end

Gemfile

source 'https://rubygems.org'
ruby '2.2.0'

gem 'activerecord', '~> 4.2', '>= 4.2.5.1'
gem 'rake'
gem 'sqlite3'
gem 'active_record_migrations' # access to rake tasks and migrations

Rakefile

require 'active_record_migrations'

ActiveRecordMigrations.load_tasks # load rake tasks