medium_schemas.ex

defmodule BlogExample.Schema.User do
  use Ecto.Schema

  schema "users" do
    field(:username, :string, null: false)
    field(:full_name, :string)

    has_many(:posts, BlogExample.Schema.Post)
    has_many(:comments, BlogExample.Schema.Comment)
  end
end


defmodule BlogExample.Schema.Post do
  use Ecto.Schema

  schema "posts" do
    field(:title, :string, null: false)
    field(:contents, :string, null: false)

    belongs_to(:user, BlogExample.Schema.User)
  end
end

defmodule BlogExample.Schema.Comment do
  use Ecto.Schema

  schema "comments" do
    field(:contents, :string, null: false)

    belongs_to(:user, BlogExample.Schema.User)
    belongs_to(:post, BlogExample.Schema.Post)
  end
end