Book Image

PostgreSQL 14 Administration Cookbook

By : Simon Riggs, Gianni Ciolli
5 (1)
Book Image

PostgreSQL 14 Administration Cookbook

5 (1)
By: Simon Riggs, Gianni Ciolli

Overview of this book

PostgreSQL is a powerful, open-source database management system with an enviable reputation for high performance and stability. With many new features in its arsenal, PostgreSQL 14 allows you to scale up your PostgreSQL infrastructure. With this book, you'll take a step-by-step, recipe-based approach to effective PostgreSQL administration. This book will get you up and running with all the latest features of PostgreSQL 14 while helping you explore the entire database ecosystem. You’ll learn how to tackle a variety of problems and pain points you may face as a database administrator such as creating tables, managing views, improving performance, and securing your database. As you make progress, the book will draw attention to important topics such as monitoring roles, validating backups, regular maintenance, and recovery of your PostgreSQL 14 database. This will help you understand roles, ensuring high availability, concurrency, and replication. Along with updated recipes, this book touches upon important areas like using generated columns, TOAST compression, PostgreSQL on the cloud, and much more. By the end of this PostgreSQL book, you’ll have gained the knowledge you need to manage your PostgreSQL 14 database efficiently, both in the cloud and on-premise.
Table of Contents (14 chapters)

Adding/removing columns on a table

As designs change, we may want to add or remove columns from our data tables. These are common operations in development, though they need more careful planning on a running production database server as they take full locks and may run for long periods.

How to do it…

You can add a new column to a table using the following command:

ALTER TABLE mytable
ADD COLUMN last_update_timestamp TIMESTAMP WITHOUT TIME ZONE;

You can drop the same column using the following command:

ALTER TABLE mytable
DROP COLUMN last_update_timestamp;

You can combine multiple operations when using ALTER TABLE, which then applies the changes in a sequence. This allows you to perform a useful trick, which is to add a column unconditionally using IF EXISTS, which is useful because ADD COLUMN does not allow IF NOT EXISTS:

ALTER TABLE mytable
DROP COLUMN IF EXISTS last_update_timestamp,ADD COLUMN last_update_timestamp TIMESTAMP...