Book Image

Learning PostgreSQL 11 - Third Edition

By : Salahaldin Juba, Andrey Volkov
Book Image

Learning PostgreSQL 11 - Third Edition

By: Salahaldin Juba, Andrey Volkov

Overview of this book

PostgreSQL is one of the most popular open source database management systems in the world, and it supports advanced features included in SQL standards. This book will familiarize you with the latest features in PostgreSQL 11, and get you up and running with building efficient PostgreSQL database solutions from scratch. Learning PostgreSQL, 11 begins by covering the concepts of relational databases and their core principles. You’ll explore the Data Definition Language (DDL) and commonly used DDL commands supported by ANSI SQL. You’ll also learn how to create tables, define integrity constraints, build indexes, and set up views and other schema objects. As you advance, you’ll come to understand Data Manipulation Language (DML) and server-side programming capabilities using PL/pgSQL, giving you a robust background to develop, tune, test, and troubleshoot your database application. The book will guide you in exploring NoSQL capabilities and connecting to your database to manipulate data objects. You’ll get to grips with using data warehousing in analytical solutions and reports, and scaling the database for high availability and performance. By the end of this book, you’ll have gained a thorough understanding of PostgreSQL 11 and developed the necessary skills to build efficient database solutions.
Table of Contents (18 chapters)

Functions and procedures – a comparison

In PostgreSQL 11, procedures were introduced. The main difference between functions and procedures is transaction control. Functions are explicitly run in a transaction, while a procedure can control transactions. In procedures, you can explicitly COMMIT and ROLLBACK a transaction. Functions can be called within SQL code, but procedures are executed via CALL statements. Finally, functions should have a return data type; if the function does not return anything, the VOID pseudo data type can be used.

Procedures have great benefits. Let's suppose that we would like to index all foreign keys. In this case, using a function is not very practical, because the indexes are created when the function completely finishes the execution. So, if an exception occurs in the middle of the execution, then all of the work is lost. In a stored...