MongoEngineNoORM for NoSQL

Serge Matveenkogithub.com/lig

PyCon Russia 2013

Quick MongoDB intro

NoSQL document-oriented database

● scalable (auto-sharding, replication)● high-performance (~104-105 queries/sec)● open source (db: AGPL, drivers: Apache)

RDBMS vs MongoDB

RDBMS MongoDB

data DB + Driver DB + PyMongo

aggregation

constraints Application

validation

cascade updates

business logic Application

RDBMS vs MongoDB

RDBMS MongoDB

data DB + Driver DB + PyMongo

aggregation

constraints MongoEngine

validation

cascade updates

business logic Application Application

MongoEngine class CharacterName(EmbeddedDocument): first = StringField() last = StringField() class Character(Document): name = EmbeddedDocumentField(CharacterName) rating = IntField()

MongoDB {"_id" : ObjectId

("5125e0ee98764119e77d9b1f"),"_types" : ["Character"],"rating" : 42,"name" : {"_types" : ["CharacterName"],

"last": "Connor", "_cls": "CharacterName", "first": "Sarah"},

"_cls": "Character"}

How it looks

MongoEngine class CharacterName(EmbeddedDocument): first = StringField() last = StringField() class Character(Document): name = EmbeddedDocumentField(CharacterName) rating = IntField()

MongoDB {"_id" : ObjectId

("5125e0ee98764119e77d9b1f"),"rating" : 42,"name" : {"last": "Connor",

"_cls": "CharacterName", "first": "Sarah"},"_cls": "Character"

}

How it looks(MongoEngine 0.8)

Simple

db.character.find({'name.first': 'John'})Character.objects(name__first='John')

db.character.find({rating: {$gte: 42}}).limit(5)Character.objects(rating__gte=42)[:5]

db.character.find({rating: {$exists: false}})Character.objects(rating__exists=False)

Querying with MongoEngine

Map/Reduce

db.character.mapReduce(map_f, reduce_f, {out: 'mr_col'});db.mr_col.find();

Character.objects.map_reduce(map_f, reduce_f, 'mr_col')

Querying with MongoEngine

Creating

db.character.save( {name: {first: 'John', last: 'Conor'}, rating: 42})

jc = Character( name=CharacterName(first='John', last='Conor'), rating=42)jc.save()

Updating with MongoEngine

Atomic updates

db.character.update( {name: {first: "John", last: "Conor"}}, {$set: {"name.last": "Connor"}})

Character.objects( name=CharacterName(first='John', last='Conor')).update(set__name__last='Connor')

Updating with MongoEngine

Under the hood

MongoDB "C" BSONModule PyMongo MongoEngine

JavaScriptConsole

Binary data

Python native types

Declarative classes

Under the hood

MongoDB "C" BSONModule PyMongo MongoEngine

JavaScriptConsole

Binary data

Python native types

Declarative classes

Performance

Out of the box● authentication backend● session engine● GridFSStorage

Third party● stephrdev/django-mongoforms (Model Forms port)● wpjunior/django-mongotools (forms, generic views)● lig/django-registration-me (django-registration port)

Django integration

Customizing things(added today. sorry:)

● SequenceField(value_decorator=func)● StringField(regex=r'…')● URLField(verify_exists=True)● …

● Inherit from standard Field classes● Write your own Field classes● Inherit from BaseDocument class,

don't forget metaclass!● Any metamagic your like…

Questions?

Serge Matveenko (github.com/lig)

mongoengine.orgwww.mongodb.org

Thanks toRoss Lawley (github.com/rozza)

Elena Voronina :)