Using Multiple Databases with django

To use multiple databases you have to tell Django about the database server you will be using, but adding them in the settings.py.

Multiple databases

    'default': {
        'NAME': 'app_data',
        'ENGINE': 'django.db.backends.postgresql',
        'USER': 'postgres_user',
        'PASSWORD': 's3krit'
    },
    'users': {
        'NAME': 'user_data',
        'ENGINE': 'django.db.backends.mysql',
        'USER': 'mysql_user',
        'PASSWORD': 'priv4te'
    }
}

The migrate management command operates on one database at a time. By default, it operates on the default database, but by providing the –database option, you can tell it to synchronize a different database.

$ ./manage.py migrate --database=users
$ ./manage.py migrate --database=customers

You can manually select the database in your queries queries e.g

user = User(....)
user.save(using='users')

Customer.objects.all().using('users')

Using raw cursor

with connections['users'].cursor() as cursor:
     cursor.execute("SELECT * FROM users__users")