Tuesday, August 29, 2006

Django with an IBM Informix backend

Update: This version of the django informix backend only works with Django pre 1.0 due to changes in Django database api. I have created a version that is known to work with Django 1.1+ and it's code can be found at: http://code.google.com/p/django-informix/

At work I needed to quickly be able to publish some technical bulletins on the web and provide a web interface for addition of new content. In the past we have used Zope for most of our in-house web development but I wanted the content stored in a "real" database. This meant deciding on a Python Web Framework that used a RDBMS out of the box. Part of the reason for selecting Django over the others, was the built-in database admin interface which meant one less set of controllers and views to develop.

Initial development was done using a SQLite backend and I had a working application deployed under lighty and fastcgi in just under a day. During this time I was also learning the framework so very impressed with the productivity. Of course good documentation and Google helped.

At work we deploy our applications on IBM Informix, Oracle and MS SQL Server databases, but for development and in-house projects use Informix. So I really needed a Django database adaptor for Informix. This would be my fourth Informix DA for a python project as I have written them for Zope2/3, and SQLObject. Writing the DA wasn't too hard but I had to do some interesting things with regular expressions to allow datetimes to work correctly and to remove some unsupported SQL syntax from the Django ORM created DDL. Also handling of TEXT data types is abit of a hack until I get a chance to re-factor the code. So if you are one of the few people in the world that still use Informix and want to use it with Django, I have put the code here. Due to Django's ORM, using some long table names you will have to use either Informix IDS 9 or 10.


Alan Green said...

Here's a few things to throw at it:

1. Slicing (e.g. queryset[5:10]) which is used to implement pagination.

2. Use order_with_respect_to in a class's meta and see what happens.

Mark Rees said...

I wasn't using pagination in my app so didn't notice the bug. I have a fixed version which only works with IDS 10 using the FIRST and SKIP keywords. Will commit it under SVN soon.