cqlengine
cqlengine is a Cassandra CQL ORM for Python in the style of the Django orm and mongoengine
NOTE: cqlengine is in alpha and under development, some features may change (hopefully with notice). Make sure to check the changelog and test your app before upgrading
Installation
pip install cqlengine
Getting Started
#first, define a model
from cqlengine import columns
from cqlengine.models import Model
class ExampleModel(Model):
read_repair_chance = 0.05 # optional - defaults to 0.1
example_id = columns.UUID(primary_key=True)
example_type = columns.Integer(index=True)
created_at = columns.DateTime()
description = columns.Text(required=False)
#next, setup the connection to your cassandra server(s)...
from cqlengine import connection
connection.setup(['127.0.0.1:9160'])
#...and create your CQL table
from cqlengine.management import create_table
create_table(ExampleModel)
#now we can create some rows:
em1 = ExampleModel.create(example_type=0, description="example1")
em2 = ExampleModel.create(example_type=0, description="example2")
em3 = ExampleModel.create(example_type=0, description="example3")
em4 = ExampleModel.create(example_type=0, description="example4")
em5 = ExampleModel.create(example_type=1, description="example5")
em6 = ExampleModel.create(example_type=1, description="example6")
em7 = ExampleModel.create(example_type=1, description="example7")
em8 = ExampleModel.create(example_type=1, description="example8")
# Note: the UUID and DateTime columns will create uuid4 and datetime.now
# values automatically if we don't specify them when creating new rows
# alternative syntax for creating new objects
ExampleModel(example_type=0, description="example9").save()
#and now we can run some queries against our table
ExampleModel.objects.count()
8
q = ExampleModel.objects(example_type=1)
q.count()
4
for instance in q:
print q.description
example5
example6
example7
example8
#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()
1
for instance in q2:
print q.description
example5