Database and Data Management - Field Guide to Hadoop - page 13

Tutorial Links

DataStax, a company that provides commercial support for Cassandra, offers a set of freely
available videos .

Example Code

The easiest way to interact with Cassandra is through its shell interface. You start the shell by
running bin/cqlsh from your install directory.

Then you need to create a keyspace. Keyspaces are similar to schemas in traditional relation-
al databases; they are a convenient way to organize your tables. A typical pattern is to use a
single different keyspace for each application:

CREATE CREATE KEYSPACE field_guide

WITH WITH REPLICATION = {

'class' : 'SimpleStrategy' , 'replication factor' : 3 } ;

USE field_guide ;

Now that you have a keyspace, you'll create a table within that keyspace to hold your re-
views. This table will have three columns and a primary key that consists of both the review-
er and the title, as that pair should be unique within the database:

CREATE CREATE TABLE TABLE reviews (

reviewer varchar ,
title varchar ,
rating int ,
PRIMARY

PRIMARY KEY KEY ( reviewer , title ));

Once your table is created, you can insert a few reviews:

INSERT INSERT INTO INTO reviews ( reviewer , title , rating )

VALUES

VALUES ( 'Kevin' , 'Dune' , 10 );
INSERT INSERT INTO INTO reviews ( reviewer , title , rating )

VALUES

VALUES ( 'Marshall' , 'Dune' , 1 );
INSERT INSERT INTO INTO reviews ( reviewer , title , rating )

VALUES VALUES ( 'Kevin' , 'Casablanca' , 5 );