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
Triggers and Rules

In the previous chapter, we talked about server-side programming. In this chapter, we will use the concepts introduced in the previous chapter to manage the programming of events in PostgreSQL. The first thing we need to address is what an event in PostgreSQL actually is. In PostgreSQL, possible events are given by the SELECT/INSERT/UPDATE, and DELETE statements. There are also events related to data definition language (DDL) operations; we will talk about those events in Chapter 17, Event Triggers.

In PostgreSQL, there are two ways to handle events:

  • Rules
  • Triggers

In this chapter, we will explore both of these ways and address when it is more appropriate to use one of them rather than the other. As a starting point, we can generally say that rules are usually simple event handlers, while triggers are more complex event handlers. Triggers and rules are often...