Book Image

Mastering PostgreSQL 12 - Third Edition

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 12 - Third Edition

By: Hans-Jürgen Schönig

Overview of this book

Thanks to its reliability, robustness, and high performance, PostgreSQL has become the most advanced open source database on the market. This third edition of Mastering PostgreSQL helps you build dynamic database solutions for enterprise applications using the latest release of PostgreSQL, which enables database analysts to design both physical and technical aspects of system architecture with ease. Starting with an introduction to the newly released features in PostgreSQL 12, this book will help you build efficient and fault-tolerant PostgreSQL applications. You’ll thoroughly examine the advanced features of PostgreSQL, including logical replication, database clusters, performance tuning, monitoring, and user management. You’ll also work with the PostgreSQL optimizer, configure PostgreSQL for high speed, and understand how to move from Oracle to PostgreSQL. As you progress through the chapters, you’ll cover transactions, locking, indexes, and how to optimize queries for improved performance. Additionally, you’ll learn how to manage network security and explore backups and replications while understanding useful PostgreSQL extensions to help you in optimizing the performance of large databases. By the end of this PostgreSQL book, you’ll be able to get the most out of your database by implementing advanced administrative tasks effortlessly.
Table of Contents (18 chapters)
Free Chapter
1
Section 1: Basic Overview
4
Section 2: Advanced Concepts

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 [, ...]

URL: https://www.postgresql.org/docs/12/sql-droprole.html

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...