Book Image

Learn PostgreSQL

By : Luca Ferrari, Enrico Pirozzi
Book Image

Learn PostgreSQL

By: Luca Ferrari, Enrico Pirozzi

Overview of this book

PostgreSQL is one of the fastest-growing open source object-relational database management systems (DBMS) in the world. As well as being easy to use, it’s scalable and highly efficient. In this book, you’ll explore PostgreSQL 12 and 13 and learn how to build database solutions using it. Complete with hands-on tutorials, this guide will teach you how to achieve the right database design required for a reliable environment. You'll learn how to install and configure a PostgreSQL server and even manage users and connections. The book then progresses to key concepts of relational databases, before taking you through the Data Definition Language (DDL) and commonly used DDL commands. To build on your skills, you’ll understand how to interact with the live cluster, create database objects, and use tools to connect to the live cluster. You’ll then get to grips with creating tables, building indexes, and designing your database schema. Later, you'll explore the Data Manipulation Language (DML) and server-side programming capabilities of PostgreSQL using PL/pgSQL, before learning how to monitor, test, and troubleshoot your database application to ensure high-performance and reliability. By the end of this book, you'll be well-versed with the Postgres database and be able to set up your own PostgreSQL instance and use it to build robust solutions.
Table of Contents (27 chapters)
Section 1: Getting Started
Section 2: Interacting with the Database
Section 3: Administering the Cluster
Section 4: Replication
Section 5: The PostegreSQL Ecosystem

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 extension that applies 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 tag Linux is a child of the tag Operating Systems and therefore the path to the tag Linux 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 tag path as in the following...