clessg / ecto_enum

Ecto extension to support enums in models

EctoEnum

EctoEnum is an Ecto extension to support enums in your Ecto models.

Usage

First, we add ecto_enum to mix.exs:

def deps do
  [{:ecto_enum, "~> 0.3.0"}]
end

We will then have to define our enum. We can do this in a separate file since defining an enum is just defining a module. We do it like:

# lib/my_app/ecto_enums.ex

import EctoEnum
defenum StatusEnum, registered: 0, active: 1, inactive: 2, archived: 3

Once defined, EctoEnum can be used like any other Ecto.Type by passing it to a field in your model's schema block. For example:

defmodule User do
  use Ecto.Model

  schema "users" do
    field :status, StatusEnum
  end
end

In the above example, the :status will behave like an enum and will allow you to pass an integer, atom or string to it. This applies to saving the model, invoking Ecto.Changeset.cast/4, or performing a query on the status field. Let's do a few examples:

iex> user = Repo.insert!(%User{status: 0})
iex> Repo.get(User, user.id).status
:registered

iex> %{changes: changes} = cast(%User{}, %{"status" => "active"}, ~w(status), [])
iex> changes.status
:active

iex> from(u in User, where: u.status == :registered) |> Repo.all() |> length
1

Passing a value that the custom Enum type does not recognize will result in an error.

iex> Repo.insert!(%User{status: :none})
** (Elixir.EctoEnum.Error) :none is not a valid enum value

The enum type StatusEnum will also have a reflection function for inspecting the enum map in runtime.

iex> StatusEnum.__enum_map__()
[registered: 0, active: 1, inactive: 2, archived: 3]

Important links

• Documentation
• License