Query Cassandra

primeight is designed to abstract the querying language used by Cassandra and to ease the creation of queries programmatically. It implements a set of methods that can be chained to construct queries (these methods return self).

Methods

• id
• time
• space
• equals
• among
• between
• between_including
• lower_than
• lower_or_equal_than
• higher_than
• higher_or_equal_than

Required Columns

The id, time, and space methods identify the required attributes of the query.

When a query have more that one required column, you can not only specify one of them, you need to specify all.

Example

from primeight.parser import YamlParser
from primeight import CassandraManager, CassandraKeyspace, CassandraTable

# Load configuration.
config = YamlParser.parse('devices.yaml')

# Connect to Cassandra cluster.
manager = CassandraManager(['127.0.0.1'])
manager.connect()

# Create Keyspace and table.
keyspace = CassandraKeyspace(config, cassandra_manager=manager)
table = CassandraTable(config, cassandra_manager=manager)

# Query table.
rows = \
    table \
    .query('base') \
    .id('659b6222-19fb-416e-9aa5-9df8cf679247') \
    .execute()
n_rows = len(rows)
print(f"Queried {len(rows)} rows")