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)

Creating the users table


Our first table will store basic user account information: username, email, and password. To create the table, fire up the CQL shell (don't forget to use the USE  my_status; statement if you are starting a fresh session) and enter the following CQL statement:

    CREATE TABLE "users" ( 
      "username" text PRIMARY KEY, 
      "email" text, 
      "encrypted_password" blob 
    );

In the preceding statement, we created a new table called users, which has three columns: username and email, which are the text columns, and encrypted_password, which has the type blob. The username column acts as the primary key for the table.

Another way to declare this table is as follows:

    CREATE TABLE "my_status"."users" (
     "username" text,
     "email" text,
     "encrypted_password" blob,
     primary key (username)
    );

Later, we will learn that the second way of declaring tables is often the only way.

Structuring of tables

Cassandra structures tables in rows and columns, just...