EmbeddedModel

A simple extension for ActiveRecord allowing to embed plain-models and store them as JSON. It's well-suited in case the use of full-featured models with underlying tables is redundant.

Add this line to your application's Gemfile:

gem 'embedded_model'

And then execute:

$ bundle

Or install it yourself as:

$ gem install embedded_model

Current version of the gem works with ActiveRecord ~> 5 only, but previous one fits well for 4.2.

gem 'embedded_model', '~> 0.1.0'

Any class allowing to populate their attributes by passing hash into constructor will suit.

class Person
  attr_accessor :name

  def initialize(attrs = {})
    @name = attrs.with_indifferent_access['name']
  end
end

I recommend using Virtus.

class Person
  include Virtus.model

  attribute :name, String
end

Add columns to be used as storage for embedded objects. If your database supports JSON (e.g. PostgreSQL), use type json, otherwise use text.

Use embeds_one method for embedding single objects and embeds_many for collections.

class Department < ActiveRecord::Base
  embeds_one :boss
  embeds_many :employees
end

By default, names of the embeddable models are inferred from the column names. Should your classes have other names, it is necessary to specify them explicitly.

class Party < ActiveRecord::Base
  embeds_one :tank, class_name: 'Player'
  embeds_many :dps, class_name: 'Player'
end

As soon as everything gets done, it simply works.

department_params = {
  boss: { name: 'Todd' },
  employees: [{ name: 'Andy' }, { name: 'Jim' }]
}

department = Department.new(department_params)

# Do something with your model objects
department.boss.command('Work!')  # => Todd commands 'Work!'
department.employees.each(&:work) # => Andy works hard Jim works hard

department.save
department.reload

# Do something else
department.boss.command('Good job!') # => Todd commands 'Good job!'
department.employees.each(&:go_home) # => Andy goes home Jim goes home

Bug reports and pull requests are welcome on GitHub at https://github.com/vasilenko/embedded_model.

The gem is available as open source under the terms of the MIT License.