Book Image

Learning PostgreSQL 10 - Second Edition

Book Image

Learning PostgreSQL 10 - Second Edition

Overview of this book

PostgreSQL is one of the most popular open source databases in the world, supporting the most advanced features included in SQL standards. This book will familiarize you with the latest features released in PostgreSQL 10. We’ll start with a thorough introduction to PostgreSQL and the new features introduced in PostgreSQL 10. We’ll cover the Data Definition Language (DDL) with an emphasis on PostgreSQL, and the common DDL commands supported by ANSI SQL. You’ll learn to create tables, define integrity constraints, build indexes, and set up views and other schema objects. Moving on, we’ll cover the concepts of Data Manipulation Language (DML) and PostgreSQL server-side programming capabilities using PL/pgSQL. We’ll also explore the NoSQL capabilities of PostgreSQL and connect to your PostgreSQL database to manipulate data objects. By the end of this book, you’ll have a thorough understanding of the basics of PostgreSQL 10 and will have the necessary skills to build efficient database solutions.
Table of Contents (23 chapters)
Title Page
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Functions


A PostgreSQL function is used to provide a distinct service, and is often composed of a set of declarations, expressions, and statements. PostgreSQL has very rich built-in functions for almost all existing data types. In this chapter, we will focus on user-defined functions. However, details about the syntax and function parameters will be covered in later chapters.

PostgreSQL native programming language

PostgreSQL supports out-of-the-box user-defined functions written in C, SQL, and PL/pgSQL. There are also three other procedural languages that come with the standard PostgreSQL distribution: PL/Tcl, PL/Python, and PL/Perl. However, one needs to create the languages in order to use it, via the CREATE EXTENSION PostgreSQL command or via the createlang utility tool. The simplest way to create a language and make it accessible to all databases is to create it in template1, directly after the PostgreSQL cluster installation. Note that one does not need to perform this step for C, SQL...