[1.5.X] Added an example of "default" database dictionary left blank; refs #19775.

Databases can have any alias you choose. However, the alias

``default`` has special significance. Django uses the database with

the alias of ``default`` when no other database has been selected. If

the concept of a ``default`` database doesn't make sense in the context

of your project, you need to be careful to always specify the database

that you want to use. Django requires that a ``default`` database entry

be defined, but the parameters can be left blank if it will not be used.

the alias of ``default`` when no other database has been selected.

The following is an example ``settings.py`` snippet defining two

databases -- a default PostgreSQL database and a MySQL database called

        }

    }

If the concept of a ``default`` database doesn't make sense in the context

of your project, you need to be careful to always specify the database

that you want to use. Django requires that a ``default`` database entry

be defined, but the parameters dictionary can be left blank if it will not be

used. The following is an example ``settings.py`` snippet defining two

non-default databases, with the ``default`` entry intentionally left empty::

    DATABASES = {

        'default': {},

        'users': {

            'NAME': 'user_data',

            'ENGINE': 'django.db.backends.mysql',

            'USER': 'mysql_user',

            'PASSWORD': 'superS3cret'

        },

        'customers': {

            'NAME': 'customer_data',

            'ENGINE': 'django.db.backends.mysql',

            'USER': 'mysql_cust',

            'PASSWORD': 'veryPriv@ate'

        }

    }

If you attempt to access a database that you haven't defined in your

:setting:`DATABASES` setting, Django will raise a

``django.db.utils.ConnectionDoesNotExist`` exception.