Question

I have an Address model and an Order model in my Rails app. An order has a billing address and a delivery address. I’m trying to figure out the most efficient way of implementing this with a polymorphic association (other models will also have addresses in future) and this is the code I’ve come up with:

address.rb:

class Address < ActiveRecord::Base
  attr_accessible :line_1, :line_2, :city, :county, :postcode
  # Also has an 'address_type' attribute

  belongs_to :addressable, polymorphic: true
end

order.rb:

class Order < ActiveRecord::Base
  has_many :addresses, as: :addressable

  def delivery_address
    addresses.where(address_type: 'delivery').first
  end

  def delivery_address=(address)
    address.address_type = 'delivery'
    addresses << address
  end

  def billing_address
    addresses.where(address_type: 'billing').first
  end

  def billing_address=(address)
    address.address_type = 'billing'
    addresses << address
  end
end

Adding an address:

Order.first.address = Address.new(line_1: 'My House', city: 'Cityville, county: 'Hazzard')

This almost works except that trying to change an address by calling order.delivery_address= again just adds another address of type ‘delivery’. I’m also pretty sure that there must be a more elegant way of doing it and I’d really appreciate any advice.

Answer 1

has_one :delivery_address, as: :addressable,
         conditions: "addresses.address_type = 'delivery'", class_name: "Address"
has_one :billing_address,  as: :addressable,
         conditions: "addresses.address_type = 'billing'", class_name: "Address"