Django Cassandra Engine - Advanced Usage

Cassandra as secondary database

Sometimes you want to use cassandra database along with your relational database. This is also possible! Just define your DATABASES like below:

    from cassandra import ConsistencyLevel

    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.sqlite3',
            'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
        },
        'cassandra': {
            'ENGINE': 'django_cassandra_engine',
            'NAME': 'db',
            'USER': 'user',
            'PASSWORD': 'pass',
            'TEST_NAME': 'test_db',
            'HOST': '127.0.0.1',
            'OPTIONS': {
                'replication': {
                    'strategy_class': 'SimpleStrategy',
                    'replication_factor': 1
                },
                'connection': {
                    'consistency': ConsistencyLevel.LOCAL_ONE,
                    'retry_connect': True
                    # + All connection options for cassandra.cluster.Cluster()
                },
                'session': {
                    'default_timeout': 10,
                    'default_fetch_size': 10000
                    # + All options for cassandra.cluster.Session()
                }
            }
        }
    }

Then run ./manage.py syncdb for your regular database and ./manage.py sync_cassandra or ./manage.py syncdb --database cassandra for Cassandra DB.

All cassandra.cluster.Cluster and cassandra.cluster.Session options are well described here .

Using internal authorization

If you want to use internal authorization just provide USER and PASSWORD in cassandra's database alias.

    ...
    'cassandra' {
        'ENGINE': 'django_cassandra_engine',
        'NAME': 'db',
        'USER': 'user',
        'PASSWORD': 'pass'
    }

You can also pass custom auth_provider to connection dict:

    ...
    'connection': {
        'consistency': ConsistencyLevel.LOCAL_ONE,
        'retry_connect': True,
        'port': 9042,
        'auth_provider': PlainTextAuthProvider(username='user', password='password')
        # + All connection options for cassandra.cluster.Cluster()
    }

Performing raw database queries

You might need to perform queries that don't map cleanly to models, or directly execute UPDATE, INSERT, or DELETE queries.

In these cases, you can always access the database directly, routing around the model layer entirely:

    from django.db import connection
    cursor = connection.cursor()
    result = cursor.execute("SELECT COUNT(*) FROM users")
    print result[0]['count']

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That was easy! Show me some useful management commands now.