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Version 33 (modified by mtredinnick, 7 years ago) (diff)

Stop tresting MySQL like a second-class citizen for no reason.

This is a work in progress, answering questions that do indeed get asked frequently on the Django IRC channel (#django on irc.freenode.net). Feel free to contribute, but try to keep it clear and concise. Please don't editorialize.

There's also a helpful official FAQ.

TOC?

General Tips

  • When asking for help in the channel, be as specific as possible in your request. "It doesn't work" is not sufficiently specific!
  • Standard problem-reporting advice: Describe 1) what you did, 2) what you expected to happen, and 3) what actually happened.
  • General problem-solving advice: Test all the things you think are true until you find the one that isn't.
  • Showing actual code is useful. For code longer than a line or two, use the pastebin: http://dpaste.com/
  • Django has very good documentation. Make sure you've checked it!

Python questions

How do I learn Python if I'm new to programming?

How do I learn Python if I'm not new to programming?

Are there any books on Python?

Yes. http://wiki.python.org/moin/PythonBooks

Django questions

Which version should I use, the 0.96 release or the Subversion checkout?

The 0.96 release is well-tested and stable, and is best for production deployments. Tracking the development version of Django through a Subversion checkout can be nice if there's a new feature you really want, but does require you to pay more attention to what's going on in Django development -- if a backwards-incompatible change is introduced, you'll need to be watching the development timeline to notice it and change your code to suit, where sticking to official releases means that you get a list of any changes you need to make in the release notes.

There will be several backwards-incompatible changes before the next release of Django (for example, the workings of the admin app will be changing), so it's officially recommended that production deployments stick to the 0.96 release until the next release is ready.

Should I read the documentation on the djangoproject.com website, or djangobook.com?

Start with the documentation here, and then have a look at the book if you're interested; the documentation on djangoproject.com includes the official tutorial, and a number of comprehensive references which aren't currently available in the book.

What does 'function' object has no attribute 'rindex' mean?

This error is a telltale sign that you're trying to use examples in the Django book with an older version of Django -- the book includes examples which rely on features introduced in Django 0.96.

How do I extend a model? I want to subclass django.contrib.auth.models.User.

You can't do this at the moment, but model subclassing is being worked on. Also, see here http://www.b-list.org/weblog/2007/02/20/about-model-subclassing and here for instructions on extending the User model: http://www.djangobook.com/en/beta/chapter12/#cn226

If I change my model, will manage.py syncdb update my database table?

No, you'll need to manually change your database table. If you use manage.py sqlall on your app to produce a SQL file before editing your models, you can run it again afterwards and use the difference between the two to see what you need to change in the database.

What should I use for development -- the built-in server, mod_python, FastCGI?

It's generally easiest to use the built-in development server, since it automatically reloads your Python source files when it detects changes. (Some prefer to replicate the production environment as closely as possible, meaning that if their deployed project uses mod_python then their development server does as well.)

What's the difference between null=True and blank=True in models?

null=True means that the database will accept a NULL value for that field; blank=True means that Django's validation system won't complain about a missing value. If you use blank=True but not null=True you will need to have your code fill in a value before storage in the database -- specifying a default on a field, or putting something in the model's save method to generate a value are two good ways to handle this, and can be extremely useful when you want to calculate one field's value based on others.

I think Ajax is awesome! How do I do Ajax with Django?

Choose your favorite excellent Javascript library and go to it. Django provides serializers to JSON and XML, which you can read about in the documentation: http://www.djangoproject.com/documentation/serialization/

Also see this helpful article from James Bennett (with bonus anti-Javascript-helpers rant!): http://www.b-list.org/weblog/2006/07/02/django-and-ajax

Is there a free CMS available for Django?

At this point there is nothing well-established (like Plone, for instance). In practice, people mean so many different things by "CMS" that it may be hard to get a straight answer. This question is often asked by newcomers; one recommendation is to learn a bit of Django and see just how easy it is to make a site that does what you want. If you're in a big rush, there's always Ellington: http://www.ellingtoncms.com/

What database should I use?

For development, most people find SQLite to be fastest and simplest to run with -- just make sure the database file and its directory are writeable by the owner of the web server process. For production, PostgreSQL and MySQL are the most thoroughly-tested of the databases Django supports, but it's best to choose based on the needs of your applications; for example, applications which do very little writing of data to the DB will enjoy the speed of SQLite, but applications which involve many complex queries or which require robust concurrent-write features like transaction isolation will probably want to look at Postgres or MySQL (and, of course, MySQL is often handy simply because many shared hosting providers have it set up by default).

The admin is working, but it can't find the Javascript and CSS and image files.

You're running the development server, right? Read this: http://www.djangoproject.com/documentation/static_files/

I'm trying to install Django on Windows and something is weird.

Have you looked here? http://code.djangoproject.com/wiki/WindowsInstall

What editor is best for Django?

Vim. No, wait, Emacs. A lot of people seem to like TextMate, too.

How do I customise the admin interface so all logged-in users can use it without screwing up anything?

The admin interface is designed for use by trusted site staff, not by any user -- if you don't trust a user with the level of access the admin application provides, you'll need to provide non-admin views for the actions you'd like to allow them to take.

How do I make extensive changes in the admin interface?

At the moment it's probably best not to; the admin app is fairly specialized and doesn't have a lot of places to customize behavior, so you'll usually end up writing less code by just rolling your own set of views. The newforms-admin branch, however, will significantly refactor the admin app to make customization much simpler.

I have created several users, but only the superuser is able to log into the admin

In .95 and prior releases, you cannot put a plain password when creating a new user in admin -- the form expects a hashed password in the format which will be stored in the database. In Django 0.96 and later, this is not a problem.

Also, keep in mind that admin access requires the "is_active" and "is_staff" boxes to be checked for the user.

When will the next release be out? -or- When will X branch be done?

"When it's done" is the short answer. Fixed release dates are rarely set, but searching or browsing the developer list (http://groups.google.com/group/django-developers/) can be informative.