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

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.

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)
 RETURNS type AS
BEGIN
 -- function logic
END;
LANGUAGE language_name

The following steps always apply to any type...