Applying Migrations

Tracked in django_migrations

python manage.py migrate applies unapplied migrations in dependency order and records them in the django_migrations table, so each runs once per database. Built-in apps (auth, admin, sessions, contenttypes) bring their own migrations. In deployment, run migrate as a separate step before (or as part of) releasing new code, and design changes to be backward compatible with the previous code version during rollout.

Applying migrations, run

I ran this with Django 6.1.1 and Python 3.12 in a demo project (shopsite with a catalog app) using SQLite. Output trimmed to the plan, the first auth migration and the catalog migration; every migration reported OK.

python manage.py migrate

Output:

Operations to perform:
  Apply all migrations: admin, auth, catalog, contenttypes, sessions
  Applying auth.0001_initial... OK
  Applying catalog.0001_initial... OK

Expand, then contract

Add new columns first and remove old ones in a later release, so old and new code can run during the rollout.

Quick check: How does Django know which migrations already ran?

• It reruns all migrations every time
• It reads file timestamps
• It asks the user
• It records them in the django_migrations table