Migrations create and modify the database tables HephaestusEcto needs to function.

The migration API is versioned. up/1 and down/1 delegate to HephaestusEcto.Migrations.Postgres, which applies incremental migration modules (V01, V02, and so on) and records the applied schema version in the workflow_instances table comment.

Usage

To use migrations in your application you'll need to generate an Ecto.Migration that wraps calls to HephaestusEcto.Migration:

mix hephaestus_ecto.gen.migration

Or manually create a migration:

defmodule MyApp.Repo.Migrations.AddHephaestus do
  use Ecto.Migration

  def up, do: HephaestusEcto.Migration.up()
  def down, do: HephaestusEcto.Migration.down()
end

This original zero-argument API is still supported and migrates to the latest available version.

Isolation with Prefixes

HephaestusEcto supports namespacing through PostgreSQL schemas (prefixes):

def up, do: HephaestusEcto.Migration.up(prefix: "private")
def down, do: HephaestusEcto.Migration.down(prefix: "private")

Versioning

Migrations are versioned and tracked via PostgreSQL table comments. Running up/1 only applies versions that haven't been run yet.

To upgrade incrementally to a specific version:

def up, do: HephaestusEcto.Migration.up(version: 2)

To migrate down to a specific version:

def down, do: HephaestusEcto.Migration.down(version: 1)

To inspect the currently applied version:

HephaestusEcto.Migration.migrated_version()