Ecto: Embedded Schemas

address.ex

use Ecto.Schema

import Ecto.Changeset

@type t :: module

# A required field for all embedded documents
@primary_key {:id, :binary_id, autogenerate: true}

schema "" do
  field :street_1, :string
  field :street_2, :string
  field :city, :string
  field :state, :string
  field :postal_code, :string
end

@spec changeset(t, %{}) :: Ecto.Changeset.t
def changeset(struct, params \\ %{}) do
  struct
  |> cast(params, [:street_1, :street_2, :city, :state, :postal_code])
  |> validate_required([:street_1, :city, :state, :postal_code])
end

order.ex

schema "orders" do
  field :subtotal, :decimal
  field :total_tax, :decimal
  field :total_shipping, :decimal
  field :total_price, :decimal
  field :payment_source, :string
  field :notes, :string

  belongs_to :user, CourseMaster.User

  embeds_one :billing_address, CourseMaster.Address, on_replace: :update
  embeds_one :shipping_address, CourseMaster.Address, on_replace: :update

  timestamps()
end

@doc """
Builds a changeset based on the `struct` and `params`.
"""
@spec changeset(t, %{}) :: Ecto.Changeset.t
def changeset(struct, params \\ %{}) do
  struct
  |> cast(params, [:total_price, :total_shipping, :subtotal, :total_tax, :payment_source, :notes])
  |> cast_embed(:billing_address, required: true)
  |> cast_embed(:shipping_address, required: false)
  |> validate_required([:total_price, :subtotal, :payment_source])
end

order_test.exs

test "changeset with invalid billing address" do
  billing_address_params = %{
    street_1: "",
    city: "Durham",
    state: "NC",
    postal_code: "27701"
  }

  changeset = Order.changeset(
    %Order{},
    params_for(:order, billing_address: billing_address_params)
  )

  refute changeset.valid?

  assert {:billing_address, {:street_1, ["can't be blank"]}} in errors_on(changeset)
end