Source: 📖 Django for Professionals ch2 p31

Updating settings.py to use PostgreSQL

To switch Django's database to use Postgres, the DATABASES configuration must be changed in settings.py. PostgreSQL requires a name, user, password, host and port to be provided, which are also handled in the DATABASES configuration.

# settings.py

...

DATABASES = {
	'default': {
		'ENGINE': 'django.db.backends.postgresql',
		'NAME': 'db_name',
		'USER': 'username',
		'PASSWORD': 'userpass',
		'HOST': 'db',
		'PORT': 5432
	}
}

...

The HOST key is set to db which is the name of the Docker service that the database will be running on (see Creating a Docker PostgreSQL database service). The PORT key is set to 5432, which is the default PostgreSQL port.

NOTE: this will not yet work, as first a database adapter must be installed — see Installing Psycopg