ActiveRecord question

gistfile1.md

AR association with special attributes

Is there a straightforward way to have an intermediate model in AR (has many through type of scenario) which adds attributes to the association?

E.g.: has_many :fruits, :through => :qualified_fruits, :class_name => 'Fruit'.

Fruit objects returned have a "quality" attribute which actually lives in :qualified_fruits.

The migration for join table :

class CreateMachineMemberships < ActiveRecord::Migration
  def change
    create_table :machine_memberships do |t|
      t.integer :role_cd, null: false
      t.belongs_to :machine
      t.belongs_to :user

      t.timestamps
    end

    add_index :machine_memberships, [:machine_id, :user_id], unique: true, name: 'index_machine_memberships_unique'
  end
end

Quick copy/paste left off one line lol

class Machine < ActiveRecord::Base
  has_many :machine_memberships, dependent: :destroy
  has_many :users, through: :machine_memberships
end

That gives you

machine.users