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

Introduction to users and groups

In order to connect interactively or via an application to a PostgreSQL database, you need to have login credentials. In particular, a database user, a user who is allowed to connect to that specific database, must exist.

Database users are somewhat similar to operating system users: they have a username and a password (usually encrypted) and are known to the PostgreSQL cluster. Similarly to operating system users, database users can be grouped into user groups in order to ease the massive administration of users.

In SQL, and therefore even in PostgreSQL, both concepts of a single user account and a group of accounts are encompassed by the concept of a role.

A role can be a single account, a group of accounts, or even both depending on how you configure it; however, in order to ease management, a role should express one and only one concept at a time: that is, it should be either a single user or a single group, but not both.

While a role can be used simultaneously...