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
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21
Index

Managing tables

In this section, we will learn how to manage tables in a database.

PostgreSQL has three types of tables:

  • Temporary tables: Very fast tables, visible only to the user who created them
  • Unlogged tables: Very fast tables to be used as support tables common to all users
  • Logged tables: Regular tables

We will now use the following steps to create a user table from scratch:

  1. Let’s connect to forumdb as the forum user:
    postgres@learn_postgresql:~$ psql -U forum forumdb
    forumdb=>
    
  2. Execute the following command:
    forumdb=> CREATE TABLE myusers (
     pk int GENERATED ALWAYS AS IDENTITY
     , username text NOT NULL
     , gecos text
     , email text NOT NULL
     , PRIMARY KEY( pk )
     , UNIQUE ( username )
     );
    CREATE TABLE
    

    The CREATE TABLE command creates a new table. The GENERATED AS IDENTITY command automatically assigns a unique value to a column.

  1. Observe what was created on...