Use UUIDs as primary key with Ecto - Phoenix Framework

ecto_table_with_uuid_primary_key.exs

defmodule Blog.Repo.Migrations.CreatePost do
  use Ecto.Migration

  def up do
    
    create table(:posts, primary_key: false) do
      add :id, :uuid, primary_key: true
      add :title, :string
      add :body, :text

      timestamps
    end

  end

  def down do
    drop table(:posts)
  end

end

post.ex

defmodule Blog.Post do
  use Blog.Web, :model

  # :binary_id is managed by drivers/adapters, it will be UUID for mysql
  #  but can be ObjectID if later you decide to use mongo
  @primary_key {:id, :binary_id, autogenerate: true}

  schema "posts" do
    field :title, :string
    field :body, :string

    timestamps
  end

  @required_fields ~w(title body)
  @optional_fields ~w()


  @doc """
  Creates a changeset based on the `model` and `params`.

  If `params` are nil, an invalid changeset is returned
  with no validation performed.
  """
  def changeset(model, params \\ :empty) do
    model
    |> cast(params, @required_fields, @optional_fields)
  end
end