Getting started

This guide is a brief introduction to Mutiny. For detailed information about the usage of invidual functions, you'll want to check the full documentation.


Mutiny allows you to protect certain database tables or columns from updates by calling simple functions in your Ecto migrations.

Currently, PostgreSQL is the only supported database, but the library is designed in such a way that adding support for other databases should be relatively straightforward.


Mutiny is designed to work with Ecto, and in fact requires it to be installed for initial setup. You can install Ecto, a database driver (so Ecto can talk to your database), and Mutiny by adding the appropriate dependencies to mix.exs:

def deps do
    {:ecto_sql, "~> 3.0"},
    {:postgrex, ">= 0.0.0"},
    {:mutiny, "~> 0.1.0"}


Under the hood, Mutiny works by calling a database function when update events occur in your database. Naturally, this function will need to be added to your database before you start using Mutiny in your migrations.

Mutiny comes with a Mix task that will create the required database function for you: mutiny.gen.migration. Be sure to supply an argument to indicate the type of database you're using:

mix mutiny.gen.migration postgres
mix ecto.migrate

If you'd rather write the migration yourself, take a look at Mutiny.create_prevent_update_function/0 and Mutiny.drop_prevent_update_function/0.


Now you're ready to start using Mutiny in your project.

Mutiny generates SQL commands that can be executed as part of an Ecto migration. Simply use Mutiny in a migration and specify the adapter that corresponds with your database.

The following migration will protect the data column of the snapshots table from updates:

defmodule MyApp.Repo.Migrations.CreateSnapshots do
  use Ecto.Migration
  use Mutiny, adapter: Mutiny.Adapters.Postgres

  def change do
    create table(:snapshots) do
      add :data, :map
      add :last_viewed, :utc_datetime

    |> protect(:data)
    |> execute()

You can also protect entire tables:


Or allow protected columns to be set to NULL:

protect(my_table, :data, nullable: true)

About NewAperio

Mutiny is built by NewAperio, LLC.

NewAperio is a web and mobile design and development studio. We offer expert Elixir and Phoenix development as part of our portfolio of services. Get in touch to see how our team can help you.