Object Mapper

cqlengine is the Cassandra CQL 3 Object Mapper packaged with this driver

Jump to Getting Started


Upgrade Guide
For migrating projects from legacy cqlengine, to the integrated product
Examples defining models, and mapping them to tables
Making Queries
Overview of query sets and filtering
Batch Queries
Working with batch mutations
Working with multiple sessions
API Documentation
Index of API documentation
Third party integrations
High-level examples in Celery and uWSGI

Frequently Asked Questions

Getting Started

import uuid
from cassandra.cqlengine import columns
from cassandra.cqlengine import connection
from datetime import datetime
from cassandra.cqlengine.management import sync_table
from cassandra.cqlengine.models import Model

#first, define a model
class ExampleModel(Model):
    example_id      = columns.UUID(primary_key=True, default=uuid.uuid4)
    example_type    = columns.Integer(index=True)
    created_at      = columns.DateTime()
    description     = columns.Text(required=False)

#next, setup the connection to your cassandra server(s)...
# see http://datastax.github.io/python-driver/api/cassandra/cluster.html for options
# the list of hosts will be passed to create a Cluster() instance
connection.setup([''], "cqlengine", protocol_version=3)

#...and create your CQL table
>>> sync_table(ExampleModel)

#now we can create some rows:
>>> em1 = ExampleModel.create(example_type=0, description="example1", created_at=datetime.now())
>>> em2 = ExampleModel.create(example_type=0, description="example2", created_at=datetime.now())
>>> em3 = ExampleModel.create(example_type=0, description="example3", created_at=datetime.now())
>>> em4 = ExampleModel.create(example_type=0, description="example4", created_at=datetime.now())
>>> em5 = ExampleModel.create(example_type=1, description="example5", created_at=datetime.now())
>>> em6 = ExampleModel.create(example_type=1, description="example6", created_at=datetime.now())
>>> em7 = ExampleModel.create(example_type=1, description="example7", created_at=datetime.now())
>>> em8 = ExampleModel.create(example_type=1, description="example8", created_at=datetime.now())

#and now we can run some queries against our table
>>> ExampleModel.objects.count()
>>> q = ExampleModel.objects(example_type=1)
>>> q.count()
>>> for instance in q:
>>>     print instance.description

#here we are applying additional filtering to an existing query
#query objects are immutable, so calling filter returns a new
#query object
>>> q2 = q.filter(example_id=em5.example_id)

>>> q2.count()
>>> for instance in q2:
>>>     print instance.description