Phoenix: Ecto migrations cheatsheet

Creating

$ mix ecto.gen.migration update_posts_table
  creating priv/repo/migrations/20160602085927_update_posts_table.exs
  ···

$ mix ecto.migrate
$ mix ecto.rollback

Creates a migration (no models).

Creating models

$ mix phoenix.gen.model Message messages user_id:integer content:text

This is only for Phoenix 1.2 or older; models aren’t available in Phoenix 1.3+.

Creating context

$ mix phx.gen.context Images Album albums title:string subtitle:string privacy:string

Migration functions

Creating tables

create table(:documents) do
  add :title, :string
  add :title, :string, size: 40
  add :title, :string, default: "Hello"
  add :title, :string, default: fragment("now()")
  add :title, :string, null: false
  add :body, :text
  add :age, :integer
  add :price, :float
  add :price, :float
  add :price, :decimal, precision: 10, scale: 2
  add :published_at, :utc_datetime
  add :group_id, references(:groups)
  add :object, :json

  timestamps  # inserted_at and updated_at
end

create_if_not_exists table(:documents) do: ... end

Other operations

alter table(:posts) do
  add :summary, :text
  modify :title, :text
  remove :views
end

rename table(:posts), :title, to: :summary
rename table(:posts), to: table(:new_posts)

drop table(:documents)
drop_if_exists table(:documents)

table(:documents)
table(:weather, prefix: :north_america)

Indices

create index(:posts, [:slug], concurrently: true)
create unique_index(:posts, [:slug])
drop index(:posts, [:name])

Execute SQL

execute "UPDATE posts SET published_at = NULL"
execute create: "posts", capped: true, size: 1024

References

• Ecto.Migration