MongoEngine NoORM for NoSQL Serge Matveenko github.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" BSON Module PyMongo MongoEngine JavaScript Console Binary data Python native types Declarative classes

Under the hood MongoDB "C" BSON Module PyMongo MongoEngine JavaScript Console 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.org www.mongodb.org Thanks to Ross Lawley (github.com/rozza) Elena Voronina :)