有一个处理 1-1 情况的简单示例。
想象一下我们有一个Car and an Engine模型和显然Car有一个Engine。所以有汽车型号的代码
defmodule MyApp.Car do
use MyApp.Web, :model
schema "cars" do
field :name, :string
has_one :engine, MyApp.Engine
timestamps
end
def changeset(model, params \\ :empty) do
model
|> cast(params, ~w(name), ~w())
|> validate_length(:name, min: 5, message: "No way it's that short")
end
end
和发动机型号
defmodule MyApp.Engine do
use MyApp.Web, :model
schema "engines" do
field :type, :string
belongs_to :car, MyApp.Car
timestamps
end
def changeset(model, params \\ :empty) do
model
|> cast(params, ~w(type), ~w())
|> validate_length(:type, max: 10, message: "No way it's that long")
end
end
表单的简单模板 ->
<%= form_for @changeset, cars_path(@conn, :create), fn c -> %>
<%= text_input c, :name %>
<%= inputs_for c, :engine, fn e -> %>
<%= text_input e, :type %>
<% end %>
<button name="button" type="submit">Create</button>
<% end %>
和控制器 ->
defmodule MyApp.CarController do
use MyApp.Web, :controller
alias MyApp.Car
alias MyApp.Engine
plug :scrub_params, "car" when action in [:create]
def new(conn, _params) do
changeset = Car.changeset(%Car{engine: %Engine{}})
render conn, "new.html", changeset: changeset
end
def create(conn, %{"car" => car_params}) do
engine_changeset = Engine.changeset(%Engine{}, car_params["engine"])
car_changeset = Car.changeset(%Car{engine: engine_changeset}, car_params)
if car_changeset.valid? do
Repo.transaction fn ->
car = Repo.insert!(car_changeset)
engine = Ecto.Model.build(car, :engine)
Repo.insert!(engine)
end
redirect conn, to: main_page_path(conn, :index)
else
render conn, "new.html", changeset: car_changeset
end
end
end
以及关于该主题的有趣博客文章也可以澄清一些事情 ->here http://blog.plataformatec.com.br/2015/08/working-with-ecto-associations-and-embeds/
