/docs/faq/usage.txt

 1FAQ: Using Django
 2=================
 3
 4Why do I get an error about importing DJANGO_SETTINGS_MODULE?
 5-------------------------------------------------------------
 6
 7Make sure that:
 8
 9    * The environment variable DJANGO_SETTINGS_MODULE is set to a
10      fully-qualified Python module (i.e. "mysite.settings").
11
12    * Said module is on ``sys.path`` (``import mysite.settings`` should work).
13
14    * The module doesn't contain syntax errors (of course).
15
16    * If you're using mod_python but *not* using Django's request handler,
17      you'll need to work around a mod_python bug related to the use of
18      ``SetEnv``; before you import anything from Django you'll need to do
19      the following::
20
21            os.environ.update(req.subprocess_env)
22
23      (where ``req`` is the mod_python request object).
24
25I can't stand your template language. Do I have to use it?
26----------------------------------------------------------
27
28We happen to think our template engine is the best thing since chunky bacon,
29but we recognize that choosing a template language runs close to religion.
30There's nothing about Django that requires using the template language, so
31if you're attached to ZPT, Cheetah, or whatever, feel free to use those.
32
33Do I have to use your model/database layer?
34-------------------------------------------
35
36Nope. Just like the template system, the model/database layer is decoupled from
37the rest of the framework.
38
39The one exception is: If you use a different database library, you won't get to
40use Django's automatically-generated admin site. That app is coupled to the
41Django database layer.
42
43How do I use image and file fields?
44-----------------------------------
45
46Using a :class:`~django.db.models.FileField` or an
47:class:`~django.db.models.ImageField` in a model takes a few steps:
48
49    #. In your settings file, you'll need to define :setting:`MEDIA_ROOT` as
50       the full path to a directory where you'd like Django to store uploaded
51       files. (For performance, these files are not stored in the database.)
52       Define :setting:`MEDIA_URL` as the base public URL of that directory.
53       Make sure that this directory is writable by the Web server's user
54       account.
55
56    #. Add the :class:`~django.db.models.FileField` or
57       :class:`~django.db.models.ImageField` to your model, making sure to
58       define the :attr:`~django.db.models.FileField.upload_to` option to tell
59       Django to which subdirectory of :setting:`MEDIA_ROOT` it should upload
60       files.
61
62    #. All that will be stored in your database is a path to the file
63       (relative to :setting:`MEDIA_ROOT`). You'll most likely want to use the
64       convenience :attr:`~django.core.files.File.url` attribute provided by
65       Django. For example, if your :class:`~django.db.models.ImageField` is
66       called ``mug_shot``, you can get the absolute path to your image in a
67       template with ``{{ object.mug_shot.url }}``.
68
69How do I make a variable available to all my templates?
70-------------------------------------------------------
71
72Sometimes your templates just all need the same thing. A common example would
73be dynamically-generated menus. At first glance, it seems logical to simply
74add a common dictionary to the template context.
75
76The correct solution is to use a ``RequestContext``. Details on how to do this
77are here: :ref:`subclassing-context-requestcontext`.