Installation

Preferably download Django from the subversion repository, svn co http://code.djangoproject.com/svn/django/trunk/ django

Using Subversion, svn checkout http://django-check-constraints.googlecode.com/svn/trunk/ django-check-constraints

Patch the Django code using the patch command (for Linux, BSD and Mac users, not sure for Windows)

$ cd django
$ patch -p0 < ../django-check-constraints/django_check_constraints.diff

Copy the check_constraints.py file into any directory of your choice (example: into your application folder).

$ python setup.py build
$ su
# python setup.py install