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)

Controlling access


We've now created a user account for our data analytics team, but so far that user can't actually do anything in our database. We'd like to give the data analytics team read access to all the data in our application's keyspace, but no ability to modify data or schema structures. To do this, we'll use the GRANT command:

GRANT SELECT PERMISSION 
ON KEYSPACE "my_status" 
TO 'data_analytics';

Now the data_analytics user can read the data from any table in the my_status keyspace; however, it can't make any modifications to anything. The SELECT permission we used above is one of six that Cassandra makes available:

Permission

Description

CQL commands allowed

SELECT

Read data

SELECT

MODIFY

Add, update, and remove data in existing tables

INSERT

UPDATE

DELETE

TRUNCATE

CREATE

Create keyspaces and tables

CREATE TABLE

CREATE KEYSPACE

ALTER

Modify the structure of existing keyspaces and tables

ALTER TABLE

CREATE INDEX

DROP INDEX

ALTER KEYSPACE

DROP

Drop existing keyspaces and tables

DROP TABLE

DROP KEYSPACE

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