This document provides an overview and introduction to MongoDB, an open-source, high-performance, schema-free, document-oriented database. It describes MongoDB's data model using documents and collections rather than tables, its dynamic queries, indexing and scaling capabilities. The document also compares MongoDB to traditional relational databases and discusses some common use cases and programming interfaces for MongoDB.

1. open-source, high-performance,
schema-free, document-oriented
database
http://www.mongodb.org/

2. “One size fits all”
no longer
RDBMS
(Oracle, MySQL)
Non-relational
New gen. OLAP
(vertica, aster, greenplum) operational stores
(“NoSQL”)

3. NoSQL really means:
non-relational next generation
operational datastores and databases

4. Scaling out
no joins +
light transactional semantics =
horizontally scalable architectures

5. Data models
no joins +
light transactional semantics =
horizontally scalable architectures
important side effect :
new data models =
improved ways to develop
applications

7. Documents and BSON
{“hello”: “world”}
{“hello”: “world”, “foo”: [{“bar”: 1}]}

8. Schema-free collections
• Dynamically typed languages
• Migrations
• Still define indexes per collection

9. Dynamic queries
• Administration
• Ease of development / familiarity

10. Atomic update modifiers

11. Focus on performance

12. Replication
Replica sets
Master - slave
master slave
master
master slave
slave slave slave
master master
slave
slave master

13. Auto-sharding
Shards
mongod mongod mongod
...
Config mongod mongod mongod
Servers
mongod
mongod
mongod
mongos mongos ...
client

14. Many supported
languages and platforms

15. Good at
• The web
• Caching
• High volume data
• Scalability

16. Less good at
• Highly transactional
• Ad-hoc business intelligence
• Problems that require SQL

17. _id
• Special key
• Present in all documents
• Unique across a Collection
• Any type you want

18. Post
{“author”: “mike”,
“date”: datetime.datetime.utcnow(),
“text”: “my blog post...”,
“tags”: [“mongodb”, “python”]}

19. Comment
{“author”: “eliot”,
“date”: datetime.datetime.utcnow(),
“text”: “great post!”}

20. New post
post = {“author”: “mike”,
“date”: datetime.datetime.utcnow(),
“text”: “my blog post...”,
“tags”: [“mongodb”, “python”]}
post_id = db.posts.save(post)

21. Embedding a comment
c = {“author”: “eliot”,
“date”: datetime.datetime.utcnow(),
“text”: “great post!”}
db.posts.update({“_id”: post_id},
{“$push”: {“comments”: c}})

22. Posts by author
db.posts.find({“author”: “mike”})

23. Last 10 posts
db.posts.find()
.sort(“date”, DESCENDING)
.limit(10)

24. Posts in the last week
last_week = datetime.datetime.utcnow() +
datetime.timedelta(days=-7)
db.posts.find({“date”: {“$gt”: last_week}})

25. Posts ending with
‘Python’
db.posts.find({“text”: re.compile(“Python$”)})

26. Posts with a tag
db.posts.find({“tags”: “mongodb”})
... and fast
db.posts.create_index(“tags”)

27. Counting posts
db.posts.count()
db.posts.find({“author”: “mike”}).count()

28. Basic paging
page = 2
page_size = 15
db.posts.find().limit(page_size)
.skip(page * page_size)

29. Migration: adding titles
• Easy - just start adding them:
post = {“author”: “mike”,
“date”: datetime.datetime.utcnow(),
“text”: “another blog post...”,
“tags”: [“meetup”, “python”],
“title”: “MongoDB @ DC Python”}
post_id = db.posts.save(post)

30. Advanced queries
• $gt, $lt, $gte, $lte, $ne, $all, $in, $nin
• where()
db.posts.find().where(“this.author == ‘mike’ ||
this.title == ‘hello’”)
• group()

31. Other cool stuff
• Aggregation and map reduce
• Capped collections
• Unique indexes
• Mongo shell
• GridFS

32. ?

33. Yes...
...but also sometimes no

34. Similar to +
• A lot of Django doesn’t depend on django.db:
• URL dispatch, templates, I18N, caching, etc.
• Some things do:
• Models
• Auth
• Sessions
• Admin

35. settings.py
DATABASE_ENGINE = ''
DATABASE_NAME = ''
DATABASE_USER = ''
DATABASE_PASSWORD = ''
DATABASE_HOST = ''
DATABASE_PORT = ''
MIDDLEWARE_CLASSES = (
'django.middleware.common.CommonMiddleware',
# 'django.contrib.sessions.middleware.SessionMiddleware',
# 'django.contrib.auth.middleware.AuthenticationMiddleware',
)
INSTALLED_APPS = (
# 'django.contrib.auth',
'django.contrib.contenttypes',
# 'django.contrib.sessions',
'django.contrib.sites',
)

36. Representing a Poll
{'question': 'Do MongoDB + Django <3 each other?',
'pub_date': datetime.datetime(2010, 1, 21),
'choices': [{'votes': 35, 'choice': 'Yes!'},
{'votes': 2, 'choice': 'No...'}]}

37. models.py (PyMongo)
def save_poll(question):
return db.polls.insert({"question": question,
"pub_date": datetime.utcnow()})
def all_polls():
return db.polls.find()
def add_choice(poll_id, choice):
db.polls.update({"_id": poll_id},
{"$push": {"choices": {"choice": choice,
"votes": 0}}})
def add_vote(poll_id, choice):
db.polls.update({"_id": poll_id},
{"$inc": {"choices.%d.votes" % choice: 1}})
http://api.mongodb.org/python

38. models.py (MongoKit)
class Poll(mongokit.Document):
structure = {"question": str,
"pub_date": datetime,
"choices": [{"choice": str,
"votes": int}]}
required_fields = ["question"]
default_values = {"pub_date": datetime.utcnow}
http://bytebucket.org/namlook/mongokit

39. models.py (Ming)
class Poll(ming.Document):
class __mongometa__:
session = session
name = "polls"
_id = ming.Field(ming.schema.ObjectId)
question = ming.Field(str, required=True)
pub_date = ming.Field(datetime.datetime,
if_missing=datetime.datetime.utcnow)
choices = ming.Field([{"choice": str,
"votes": int}])
http://merciless.sourceforge.net/

40. mango - sessions and auth
• Full sessions support
• mango provided User class
• supports is_authenticated(), set_password(), etc.
http://github.com/vpulim/mango

41. mango - sessions and auth
SESSION_ENGINE = 'mango.session'
AUTHENTICATION_BACKENDS = ('mango.auth.Backend',)
MONGODB_HOST = 'localhost'
MONGODB_PORT = None
MONGODB_NAME = 'mydb'
http://github.com/vpulim/mango

42. What about admin?
• No great solution... yet.
• Could replace admin app like mango does
for sessions / auth
• Or...

43. Supporting MongoDB
in django.db
• Best solution (long term)
• http://bitbucket.org/kpot/django-mongodb/
• http://bitbucket.org/wkornewald/django-nonrel/
• http://code.djangoproject.com/wiki/NonSqlBackends

44. 1. Download MongoDB
http://www.mongodb.org
2. Try it out!
3. Let us know what you think.

45. NoSQL Live from Boston
Thursday, March 11
http://www.10gen.com/events

46. • http://api.mongodb.org/python
• http://www.mongodb.org
• irc.freenode.net#mongodb
• mongodb-user on google groups
• @mongodb, @mdirolf
• mike@10gen.com