Book Image

Learn PostgreSQL - Second Edition

By : Luca Ferrari, Enrico Pirozzi
1 (2)
Book Image

Learn PostgreSQL - Second Edition

1 (2)
By: Luca Ferrari, Enrico Pirozzi

Overview of this book

The latest edition of this PostgreSQL book will help you to start using PostgreSQL from absolute scratch, helping you to quickly understand the internal workings of the database. With a structured approach and practical examples, go on a journey that covers the basics, from SQL statements and how to run server-side programs, to configuring, managing, securing, and optimizing database performance. This new edition will not only help you get to grips with all the recent changes within the PostgreSQL ecosystem but will also dig deeper into concepts like partitioning and replication with a fresh set of examples. The book is also equipped with Docker images for each chapter which makes the learning experience faster and easier. Starting with the absolute basics of databases, the book sails through to advanced concepts like window functions, logging, auditing, extending the database, configuration, partitioning, and replication. It will also help you seamlessly migrate your existing database system to PostgreSQL and contains a dedicated chapter on disaster recovery. Each chapter ends with practice questions to test your learning at regular intervals. By the end of this book, you will be able to install, configure, manage, and develop applications against a PostgreSQL database.
Table of Contents (22 chapters)
20
Other Books You May Enjoy
21
Index

Managing roles

Roles can be managed by means of three main SQL statements: CREATE ROLE to create a role from scratch, ALTER ROLE to change some role properties (for example, the login password), and DROP ROLE to remove an existing role.

PostgreSQL ships with operating system tools to manage roles: createuser and dropuser. Both these commands open a connection to the cluster and perform the SQL commands mentioned above; therefore, the usage of these tools will not be explained in this chapter.

In order to use the SQL statements to create new roles and then manage them, it is necessary to connect to a database in the cluster. The superuser role postgres can be used to that aim, at least initially, since such a role is created when the database cluster is initialized. Using the postgres role and a template database is the most common way to create your initial roles.

A role is identified by a string that represents the role name, or better, the account name of...