Python Data Persistence – Python Cassandra Driver
Cassandra’s Python module has been provided by apache itself. It works with the latest version CQL version 3 and uses Cassandra’s native protocol. This Python driver also has ORM API in addition to core API which is similar in many ways to DB-API.
To install this module, use the pip installer as always.
E:\python37>scripts\pip3 install Cassandra-driver
Verify successful installation by following commands:
- Python Data Persistence – SQLAlchemy Core
- Python Data Persistence – Python – Cassandra
- Data Persistence – Python – PyMongo
Example
>>> import cassandra >>> print (cassandra.__version__) 3.17.0
To execute CQL queries, we have to set up a Cluster object, first.
Example
>>> from cassandra.cluster import Cluster >>> clstr=Cluster( )
Next up, we need to start a session by establishing a connection with our keyspace in the cluster.
Example
>>> session=clstr.connect('mykeyspace')
The ubiquitous execute( ) method of the session object is used to perform all CQL operations. For instance, the primary SELECT query over the ‘products’ table in ‘niykeypace’ returns a result set object. Using atypical for loop, all rows can be traversed.
Example
#cassandra-select.py from cassandra.cluster import
Cluster clstr=Cluster() session=clstr.connect(1mykeyspace1) .
rows=session.execute("select * from products;") for row in rows:
print (’Manufacturer: {} ProductID:{} Name:{ }
priceformat(row[1] ,row [0] ,
row [2], row [3]) )
Output
E:\python37>python cassandra-select.py Manufacturer: ’Epson’ ProductID:5 Name:1 Printer’ price:9000 Manufacturer: 1IBall’ ProductID:10 Name:’Keyboard1 price : 1000 Manufacturer: ’Acer’ ProductID:l Name:’Laptop’ price:25000 Manufacturer: ’Acer’ ProductID:8 Name:’Tab’ price:10000 Manufacturer: ’Samsung’ ProductID:2 Name:’TV’ price:40000 Manufacturer: ’Epson’ ProductID:4 Name:1 Scanner’ price:5000 Manufacturer: ’IBall’ ProductID:7 Name:’Mouse' price:500 Manufacturer: ’Samsung’ ProductID:6 Name:’Mobile’ price:15000 Manufacturer: ’Samsung’ ProductID:9 Name:’AC’ price:35000 Manufacturer: ’IBall’ ProductID:3 Name:’Router’ price:2000