Book Image

Mastering PostgreSQL 11 - Second Edition

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 11 - Second Edition

By: Hans-Jürgen Schönig

Overview of this book

This second edition of Mastering PostgreSQL 11 helps you build dynamic database solutions for enterprise applications using the latest release of PostgreSQL, which enables database analysts to design both the physical and technical aspects of the system architecture with ease. This book begins with an introduction to the newly released features in PostgreSQL 11 to help you build efficient and fault-tolerant PostgreSQL applications. You’ll examine all of the advanced aspects of PostgreSQL in detail, including logical replication, database clusters, performance tuning, monitoring, and user management. You will also work with the PostgreSQL optimizer, configuring PostgreSQL for high speed, and see how to move from Oracle to PostgreSQL. As you progress through the chapters, you will cover transactions, locking, indexes, and optimizing queries to improve performance. Additionally, you’ll learn to manage network security and explore backups and replications, while understanding the useful extensions of PostgreSQL so that you can optimize the speed and performance of large databases. By the end of this book, you will be able to use your database to its utmost capacity by implementing advanced administrative tasks with ease.
Table of Contents (15 chapters)
Free Chapter
1
PostgreSQL Overview

Reassigning objects and dropping users

After assigning permissions and restricting access, it can happen that users will be dropped from the system. Unsurprisingly, the commands to do that are the DROP ROLE and DROP USER commands:

test=# \h DROP ROLE  
Command:  DROP ROLE 
Description: remove a database role 
Syntax: 
DROP ROLE  [ IF EXISTS ] name  [, ...] 

Let's give it a try. The following listing shows how this works:

test=# DROP ROLE joe; 
ERROR: role "joe" cannot be dropped because some objects depend on it DETAIL: target of policy joe_pol_3 on table t_person target of policy joe_pol_2 on table t_person target of policy joe_pol_1 on table t_person privileges for table t_person owner of table t_user owner of sequence t_user_id_seq owner of default privileges on new relations belonging to role joe in schema public owner of table t_useful

PostgreSQL...