Django (1.5) is workin’ fine for me, but when I fire up the Python interpreter (Python 3) to check some things, I get the weirdest error when I try importing – from django.contrib.auth.models import User –

Traceback (most recent call last):
  File "/usr/local/lib/python3.2/dist-packages/django/conf/__init__.py", line 36, in _setup
    settings_module = os.environ[ENVIRONMENT_VARIABLE]
  File "/usr/lib/python3.2/os.py", line 450, in __getitem__
    value = self._data[self.encodekey(key)]
KeyError: b'DJANGO_SETTINGS_MODULE'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.2/dist-packages/django/contrib/auth/models.py", line 8, in <module>
    from django.db import models
  File "/usr/local/lib/python3.2/dist-packages/django/db/__init__.py", line 11, in <module>
    if settings.DATABASES and DEFAULT_DB_ALIAS not in settings.DATABASES:
  File "/usr/local/lib/python3.2/dist-packages/django/conf/__init__.py", line 52, in __getattr__
    self._setup(name)
  File "/usr/local/lib/python3.2/dist-packages/django/conf/__init__.py", line 45, in _setup
    % (desc, ENVIRONMENT_VARIABLE))

django.core.exceptions.ImproperlyConfigured: Requested setting DATABASES, 
  but settings are not configured. You must either define the environment 
  variable DJANGO_SETTINGS_MODULE or call settings.configure() 
  before accessing settings.

How could it be improperly configured, when it works fine outside the Python interpreter? In my Django settings, the DATABASES settings are:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2', # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'.
        'NAME': 'django_db', # Or path to database file if using sqlite3.
        # The following settings are not used with sqlite3:
        'USER': 'zamphatta',
        'PASSWORD': 'mypassword91',
        'HOST': '', # Empty for localhost through domain sockets or '127.0.0.1' for localhost through TCP.
        'PORT': '', # Set to empty string for default.
    }
}

…how is this improperly configured?

You can’t just fire up Python and check things, Django doesn’t know what project you want to work on. You have to do one of these things:

• Use python manage.py shell
• Use django-admin.py shell --settings=mysite.settings (or whatever settings module you use)
• Set DJANGO_SETTINGS_MODULE environment variable in your OS to mysite.settings

• (This is removed in Django 1.6) Use setup_environ in the python interpreter:

  from django.core.management import setup_environ
  from mysite import settings
  
  setup_environ(settings)
  

Naturally, the first way is the easiest.

In your python shell/ipython do:

from django.conf import settings

settings.configure()

In 2017 with django 1.11.5 and python 3.6 (from the comment this also works with Python 2.7):

import django
import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mysite.settings")
django.setup()

The .py in which you put this code should be in mysite (the parent one)

On Django 1.9, I tried django-admin runserver and got the same error, but when I used python manage.py runserver I got the intended result. This may solve this error for a lot of people!

In my case, I got this when trying to run Django tests through PyCharm. I think it is because PyCharm does not load the initial Django project settings, i.e. those that manage.py shell runs initially. One can add them to the start of the testing script or just run the tests using manage.py test.

Versions:

• Python 3.5 (in virtualenv)
• PyCharm 2016.3.2 Professional
• Django 1.10

in my own case in django 1.10.1 running on python2.7.11, I was trying to start the server using django-admin runserver instead of manage.py runserver in my project directory.

For people using IntelliJ, with these settings I was able to query from the shell (on windows).