Book Image

Mastering PostgreSQL 13 - Fourth Edition

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 13 - Fourth Edition

By: Hans-Jürgen Schönig

Overview of this book

Thanks to its reliability, robustness, and high performance, PostgreSQL has become one of the most advanced open source databases on the market. This updated fourth edition will help you understand PostgreSQL administration and how to build dynamic database solutions for enterprise apps with the latest release of PostgreSQL, including designing both physical and technical aspects of the system architecture with ease. Starting with an introduction to the new features in PostgreSQL 13, this book will guide you in building efficient and fault-tolerant PostgreSQL apps. You’ll explore advanced PostgreSQL features, such as logical replication, database clusters, performance tuning, advanced indexing, monitoring, and user management, to manage and maintain your database. You’ll then work with the PostgreSQL optimizer, configure PostgreSQL for high speed, and move from Oracle to PostgreSQL. The book also covers transactions, locking, and indexes, and shows you how to improve performance with query optimization. You’ll also focus on how to manage network security and work with backups and replication while exploring useful PostgreSQL extensions that optimize 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 executing advanced administrative tasks.
Table of Contents (15 chapters)

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 this are the DROP ROLE and DROP USER commands. Here is the syntax of DROP ROLE:

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

URL: https://www.postgresql.org/docs/13/sql-droprole.html

Once the syntax of DROP ROLE has been discussed, we can 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...