Django is awesome.

I inspired a friend who is working on a administration tool for his municipal transportation agency to have a look at python and django.

I think the endless tirade of buzzwords like multiple inheritance, context managers, list comprehensions or generators made the seasoned C# programmer curious to see what the cool kids do these days.

Inspired by Uncle Bob’s Clean Architecture talks I tend to fend off all questions about which database to use with an uninvolved “It’s an implementation detail, I don’t care”, however it quickly became clear that it doesn’t work when the database has already been implemented, and at that in a database framework I was unfamiliar with: MSSQL

I was working on his computer running Microsoft Windows 7,without my carefully tuned Pycharm IDE, with a fresh installation of Python2.7.10 and the windows command line. I felt a little bit like David Beazley in his “Vault” in Discovering Python.

I had one chance to impress my friend with django, and I had virtually no tools available…

But as I said, django is awesome.

My friend watched me struggle with pip for a while and then went to a nearby shop to get some snacks.

To import an existing database into django we need two things:

  1. Be able to talk to the database
  2. Translate the database format into models for django

django-mssql

I didn’t know there was a database adapter for mssql, but it turns out there is one. django-mssql allows you to connect to the mssql2014 instance running on localhost. To install it just do:

pip install django==1.7 django-mssql

Note that at the time of writing django-mssql only ran on django 1.7 for me.

Then you can hook up you database into django:

DATABASES = {
    'default': {
        'NAME': 'transactions',
        'ENGINE': 'sqlserver_ado',
        'HOST': '127.0.0.1',
        'PORT': '50824',
        'USER': 'root',
        'PASSWORD': 'root',
    }
} Note that `HOST` must be an IP address if you're specifying `PORT`.

inspectdb

After installing django-mssql I was more than just a little anxious to type python manage.py shell, but django connected to the database just fine.

python manage.py inspectdb is a superpower of django that is going to parse the tables in a connected database and spit out python classes describing them:

class transactions2(models.Model):
    id = models.IntegerField(null=True, blank=True)
    bill_number = models.IntegerField(null=True, blank=True)
    .... so this little gem saved the day: `python manage.py inspectdb > testapp/models.py`

Typing python manage.py migrate right away is going to fail unfortunately because the inspectdb tool doesn’t know that id is special. You should modify the id line in your newly acquired models.py:

class transactions2(models.Model):
    ...
    id = models.IntegerField(primary_key=True)
    ... `python manage.py migrate` will now work just fine and djangofy the database, giving it  tables for migration history and user management.

To get the most impressive effect right away I modified testapp/admin.py:

from django.contrib import admin
from models import transactions2
admin.site.register(transactions2)

To shock my friend entirely I also created a superuser:

python manage.py createsuperuser

When my friend came back about 20 minutes later I had his application imported into django with the admin interface giving him fully editable tables, the ability to add new entries to his tables and user management already implemented. He was speechless.

Now he’s bombarding me with questions about templates and views and on a great journey from C# to Python.

Today was a good day.