Book Image

Learning Apache Cassandra - Second Edition

Book Image

Learning Apache Cassandra - Second Edition

Overview of this book

Cassandra is a distributed database that stands out thanks to its robust feature set and intuitive interface, while providing high availability and scalability of a distributed data store. This book will introduce you to the rich feature set offered by Cassandra, and empower you to create and manage a highly scalable, performant and fault-tolerant database layer. The book starts by explaining the new features implemented in Cassandra 3.x and get you set up with Cassandra. Then you’ll walk through data modeling in Cassandra and the rich feature set available to design a flexible schema. Next you’ll learn to create tables with composite partition keys, collections and user-defined types and get to know different methods to avoid denormalization of data. You will then proceed to create user-defined functions and aggregates in Cassandra. Then, you will set up a multi node cluster and see how the dynamics of Cassandra change with it. Finally, you will implement some application-level optimizations using a Java client. By the end of this book, you'll be fully equipped to build powerful, scalable Cassandra database layers for your applications.
Table of Contents (14 chapters)

Authorization in action


Now that we know how to create user accounts and grant and revoke permissions to them, let's see how a non-superuser account behaves in practice. To do this, let's open up a new cqlsh session logged in with our data analytics team's account:

$ cqlsh -u data_analytics -p verystrongpassword -k my_status

The -k my_status option simply tells cqlsh that we want to interact with the my_status keyspace, saving us the effort of issuing a USE statement.

Now let's see what we can do. First, we expect to be able to read data with no problem; let's have a look at the user_status_updates table:

SELECT * FROM user_status_updates; 

As expected, we have permission to read the contents of that table:

Now let's try making a change to some data. Though our analytics team certainly would have no malicious intent, perhaps at some point the analytics cat may sit on a keyboard, producing the following statement:

DELETE FROM "users" 
WHERE "username" = 'alice';

That's quite an alarming query, but...