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

Exploring functions and languages

PostgreSQL is capable of executing server-side code. There are many ways to provide PostgreSQL with the code to be executed. For example, the user can create functions in different programming languages. The main languages ​​supported by PostgreSQL are as follows:

  • SQL
  • PL/pgSQL
  • C

These listed languages are the built-in languages; there are also other languages that PostgreSQL can manage, but before using them, we need to install them on our system. Some of these other supported languages ​​are as follows:

  • PL/Python
  • PL/Perl
  • PL/tcl
  • PL/Java

In this section, we'll talk about SQL and PL/pgSQL functions.


The command structure with which a function is defined is as follows:

CREATE FUNCTION function_name(p1 type, p2 type,p3 type, ....., pn type)
-- function logic
LANGUAGE language_name

The following steps always apply for any type of function we want to create:

  1. Specify the name of the function...