django/docs/releases/0.96.txt

.. _releases-0.96:

=================================
Django version 0.96 release notes
=================================

Welcome to Django 0.96!

The primary goal for 0.96 is a cleanup and stabilization of the features
introduced in 0.95. There have been a few small `backwards-incompatible
changes`_ since 0.95, but the upgrade process should be fairly simple
and should not require major changes to existing applications.

However, we're also releasing 0.96 now because we have a set of
backwards-incompatible changes scheduled for the near future. Once
completed, they will involve some code changes for application
developers, so we recommend that you stick with Django 0.96 until the
next official release; then you'll be able to upgrade in one step
instead of needing to make incremental changes to keep up with the
development version of Django.

Backwards-incompatible changes
==============================

The following changes may require you to update your code when you switch from
0.95 to 0.96:

``MySQLdb`` version requirement
-------------------------------

Due to a bug in older versions of the ``MySQLdb`` Python module (which
Django uses to connect to MySQL databases), Django's MySQL backend now
requires version 1.2.1p2 or higher of ``MySQLdb``, and will raise
exceptions if you attempt to use an older version.

If you're currently unable to upgrade your copy of ``MySQLdb`` to meet
this requirement, a separate, backwards-compatible backend, called
"mysql_old", has been added to Django. To use this backend, change
the :setting:`DATABASE_ENGINE` setting in your Django settings file from
this::

    DATABASE_ENGINE = "mysql"

to this::

    DATABASE_ENGINE = "mysql_old"

However, we strongly encourage MySQL users to upgrade to a more recent
version of ``MySQLdb`` as soon as possible, The "mysql_old" backend is
provided only to ease this transition, and is considered deprecated;
aside from any necessary security fixes, it will not be actively
maintained, and it will be removed in a future release of Django.

Also, note that some features, like the new :setting:`DATABASE_OPTIONS`
setting (see the `databases documentation`_ for details), are only
available on the "mysql" backend, and will not be made available for
"mysql_old".

.. _databases documentation: http://www.djangoproject.com/documentation/0.96/databases/

Database constraint names changed
---------------------------------

The format of the constraint names Django generates for foreign key
references have changed slightly. These names are generally only used
when it is not possible to put the reference directly on the affected
column, so they are not always visible.

The effect of this change is that running ``manage.py reset`` and
similar commands against an existing database may generate SQL with
the new form of constraint name, while the database itself contains
constraints named in the old form; this will cause the database server
to raise an error message about modifying non-existent constraints.

If you need to work around this, there are two methods available:

    1. Redirect the output of ``manage.py`` to a file, and edit the
       generated SQL to use the correct constraint names before
       executing it.

    2. Examine the output of ``manage.py sqlall`` to see the new-style
       constraint names, and use that as a guide to rename existing
       constraints in your database.

Name changes in ``manage.py``
-----------------------------

A few of the options to ``manage.py`` have changed with the addition of fixture
support:

    * There are new ``dumpdata`` and ``loaddata`` commands which, as
      you might expect, will dump and load data to/from the
      database. These commands can operate against any of Django's
      supported serialization formats.

    * The ``sqlinitialdata`` command has been renamed to ``sqlcustom`` to
      emphasize that ``loaddata`` should be used for data (and ``sqlcustom`` for
      other custom SQL -- views, stored procedures, etc.).

    * The vestigial ``install`` command has been removed. Use ``syncdb``.

Backslash escaping changed
--------------------------

The Django database API now escapes backslashes given as query parameters. If
you have any database API code that matches backslashes, and it was working before
(despite the lack of escaping), you'll have to change your code to "unescape" the
slashes one level.

For example, this used to work::

    # Find text containing a single backslash
    MyModel.objects.filter(text__contains='\\\\')

The above is now incorrect, and should be rewritten as::

    # Find text containing a single backslash
    MyModel.objects.filter(text__contains='\\')

Removed ENABLE_PSYCO setting
----------------------------

The ``ENABLE_PSYCO`` setting no longer exists. If your settings file includes
``ENABLE_PSYCO`` it will have no effect; to use Psyco_, we recommend
writing a middleware class to activate it.

.. _psyco: http://psyco.sourceforge.net/

What's new in 0.96?
===================

This revision represents over a thousand source commits and over four hundred
bug fixes, so we can't possibly catalog all the changes. Here, we describe the
most notable changes in this release.

New forms library
-----------------

``django.newforms`` is Django's new form-handling library. It's a
replacement for ``django.forms``, the old form/manipulator/validation
framework.  Both APIs are available in 0.96, but over the next two
releases we plan to switch completely to the new forms system, and
deprecate and remove the old system.

There are three elements to this transition:

    * We've copied the current ``django.forms`` to
      ``django.oldforms``. This allows you to upgrade your code *now*
      rather than waiting for the backwards-incompatible change and
      rushing to fix your code after the fact.  Just change your
      import statements like this::

          from django import forms             # 0.95-style
          from django import oldforms as forms # 0.96-style

    * The next official release of Django will move the current
      ``django.newforms`` to ``django.forms``. This will be a
      backwards-incompatible change, and anyone still using the old
      version of ``django.forms`` at that time will need to change
      their import statements as described above.

    * The next release after that will completely remove
      ``django.oldforms``.

Although the ``newforms`` library will continue to evolve, it's ready for use
for most common cases. We recommend that anyone new to form handling skip the
old forms system and start with the new.

For more information about ``django.newforms``, read the `newforms
documentation`_.

.. _newforms documentation: http://www.djangoproject.com/documentation/0.96/newforms/

URLconf improvements
--------------------

You can now use any callable as the callback in URLconfs (previously, only
strings that referred to callables were allowed). This allows a much more
natural use of URLconfs. For example, this URLconf::

    from django.conf.urls.defaults import *

    urlpatterns = patterns('',
        ('^myview/$', 'mysite.myapp.views.myview')
    )

can now be rewritten as::

    from django.conf.urls.defaults import *
    from mysite.myapp.views import myview

    urlpatterns = patterns('',
        ('^myview/$', myview)
    )

One useful application of this can be seen when using decorators; this
change allows you to apply decorators to views *in your
URLconf*. Thus, you can make a generic view require login very
easily::

    from django.conf.urls.defaults import *
    from django.contrib.auth.decorators import login_required
    from django.views.generic.list_detail import object_list
    from mysite.myapp.models import MyModel

    info = {
        "queryset" : MyModel.objects.all(),
    }

    urlpatterns = patterns('',
        ('^myview/$', login_required(object_list), info)
    )

Note that both syntaxes (strings and callables) are valid, and will continue to
be valid for the foreseeable future.

The test framework
------------------

Django now includes a test framework so you can start transmuting fear into
boredom (with apologies to Kent Beck). You can write tests based on doctest_
or unittest_ and test your views with a simple test client.

There is also new support for "fixtures" -- initial data, stored in any of the
supported `serialization formats`_, that will be loaded into your database at the
start of your tests. This makes testing with real data much easier.

See `the testing documentation`_ for the full details.

.. _doctest: http://docs.python.org/library/doctest.html
.. _unittest: http://docs.python.org/library/unittest.html
.. _the testing documentation: http://www.djangoproject.com/documentation/0.96/testing/
.. _serialization formats: http://www.djangoproject.com/documentation/0.96/serialization/

Improvements to the admin interface
-----------------------------------

A small change, but a very nice one: dedicated views for adding and
updating users have been added to the admin interface, so you no
longer need to worry about working with hashed passwords in the admin.

Thanks
======

Since 0.95, a number of people have stepped forward and taken a major
new role in Django's development. We'd like to thank these people for
all their hard work:

    * Russell Keith-Magee and Malcolm Tredinnick for their major code
      contributions. This release wouldn't have been possible without them.

    * Our new release manager, James Bennett, for his work in getting out
      0.95.1, 0.96, and (hopefully) future release.

    * Our ticket managers Chris Beaven (aka SmileyChris), Simon Greenhill,
      Michael Radziej, and Gary Wilson. They agreed to take on the monumental
      task of wrangling our tickets into nicely cataloged submission. Figuring
      out what to work on is now about a million times easier; thanks again,
      guys.

    * Everyone who submitted a bug report, patch or ticket comment. We can't
      possibly thank everyone by name -- over 200 developers submitted patches
      that went into 0.96 -- but everyone who's contributed to Django is listed
      in AUTHORS_.

.. _AUTHORS: http://code.djangoproject.com/browser/django/trunk/AUTHORS