This document discusses options for using Django with MongoDB, including object-document mappers like MongoEngine and Mongokit. It notes that some Django contrib apps may be broken but the admin will work. Benefits highlighted include reduced impedance mismatch, support for new fields like aggregations, gridfs, caching, map reduce, and indexes. Suggestions include using raw queries, embedding documents when possible, rethinking models, only using MongoDB for certain apps/models, serving static files via GridFS, and leveraging aggregations and map/reduce. It warns against migrating data and notes dates work but month/day queries do not.

1. So you want to use
DJANGO AND
MONGODB
@flaper87

2. DJANGO AND
MONGODB
THAT’S COOL, but you need
to know A COUPLE OF THINGS

3. LIKE: WHAT ARE
THE OPTIONS?

4. ( http://mongoengine.org )
An object-document mapper
to connect Python and MongoDB

5. Mongokit
( http://namlook.github.com/mongokit/ )
Another ODM
that takes mongodb into the web

6. OR, OF COURSE

7. DJANGO
MONGODB
ENGINE
(A MongoDB backend for Django)

8. DJANGO-NONREL
A good and up to date Django fork
that brings non-rel support

9. Sadly, some of your
django.contrib.*
may be broken, but not the admin

10. erm... OKAY
WHAT’S SO COOL
ABOUT THIS THEN?

11. WHAT’S SO COOL
ABOUT THIS THEN?
No changes needed.

12. ABOUT THIS THEN?
No changes needed.
NOBODY’S GONNA TOUCH
YOUR PRECIOUS BUILTINS.

13. NOBODY’S GONNA TOUCH
YOUR PRECIOUS BUILTINS.
REDUCED IMPEDANCE MISSMATCH

14. That’s cool
WHAT ELSE?

15. NEW FIELDS

16. AGGREGATIONS

17. GRIDFS

18. CACHING

19. MAP / REDUCE
>>> for pair in Article.objects.map_reduce(_map, _reduce, 'wordcount'):
... print pair.key, pair.value

20. NEW INDEXES
class Club(models.Model):
location = ListField()
rating = models.FloatField()
...
class MongoMeta:
indexes = [
[('rating', -1)],
{'fields': [('location', '2d')], 'min': -42, 'max': 42},
]

21. Plus:
TONS OF DOCS
(which never hurts)

22. Suggestions

23. RAW QUERIES
MyModel.objects.raw_query(field=“value”)

24. EMBEDD IF
POSSIBLE
class Comment(models.Model):
created_on = models.DateTimeField()
author = EmbeddedModelField('Author')
text = models.TextField()

25. RE-THINK
YOUR MODELS
class Post(models.Model):
title = models.CharField()
text = models.TextField()
tags = ListField()
# Note: Use defer
comments = ListField(EmbeddedModelField('Comment'))

26. DO NOT USE IT
EVERYWHERE
MONGODB_MANAGED_APPS = ['myapp']
MONGODB_MANAGED_MODELS = ['myapp.MongoDBModel']

27. SERVE STATIC
FILES
GridFSStorage + nginx-GridFS

28. AGGREGATIONS?
MAP/REDUCE
class Min(MongoAggregate):
initial_value = float('inf')
reduce_template = '{alias} = ({lookup}<{alias})?{lookup}:{alias}'
class Max(MongoAggregate):
initial_value = float('-inf')
reduce_template = '{alias} = ({lookup}>{alias})?{lookup}:{alias}'

29. DATES WORK
But, MongoDB
does not support month/day queries

30. DO NOT TRY
TO MIGRATE
It Wont Work!

31. CONTRIBUTE
The Compiler’s a mess

32. Ask away
http://groups.google.com
/group/django-non-relational
Contribute:
http://django-mongodb.org
/meta/contributing.html