Ecto.Migration ofera un DSL independent de baza de date pentru scrierea si rularea migrarilor.
Comenzi CLI de migrare (CLI Migration Commands)
# Generare fisier de migrare
mix ecto.gen.migration add_status_to_orders
# Rulare migrari in asteptare
mix ecto.migrate
# Revenire la pasul anterior de migrare
mix ecto.rollback
# Verificare stare migrari
mix ecto.migrations
DSL de definire a tabelelor (Table Definition DSL)
defmodule MyApp.Repo.Migrations.CreateDocuments do
use Ecto.Migration
def change do
create table(:documents) do
add :title, :string, size: 100, null: false
add :body, :text
add :price, :decimal, precision: 10, scale: 2
add :views, :integer, default: 0
add :active, :boolean, default: true, null: false
add :metadata, :map # JSON / JSONB
add :published_at, :utc_datetime
# Referinta cheie straina
add :author_id, references(:users, on_delete: :delete_all), null: false
# Adauga inserted_at si updated_at
timestamps()
end
end
end
Modificarea tabelelor existente (alter)
alter table(:documents) do
add :subtitle, :string
modify :title, :string, size: 255
remove :views
end
Indici și constrângeri (Indices & Constraints)
# Indice unic
create unique_index(:users, [:email])
# Indice compus cu creare concurenta (PostgreSQL)
create index(:orders, [:user_id, :status], concurrently: true)
# Stergere indice
drop index(:orders, [:status])
Executare SQL brut (Raw SQL)
# Executare comenzi SQL arbitrare in migrare
execute "CREATE EXTENSION IF NOT EXISTS citext;"