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

Creating your own extension

In this section, we will build an extension from scratch so that you will better understand how they are made up. The idea is to let you know how to convert even your own SQL scripts into an extension, with all the advantages that an extension can provide in terms of manageability.

Defining an example extension

In order to demonstrate how to build your own extension, we are going to create a simple set of capabilities that apply to the forum database, providing some more features. In particular, we are going to define an extension named tagext that will provide a utility function that, given a particular tag within the tag table, will return the full path to that tag with all ancestors.

For example, the Linux tag is a child of the Operating Systems tag, and therefore the path to the Linux tag is Operating System > Linux.

In particular, we want our extension to provide us with a function named tag_path that, given a tag, provides the...