Postgresql Access Control - postgresql

Question

I am trying to create a Postgresql database with a new owner for which I did the following:
postgres=# create user saurabhd;
postgres=# CREATE DATABASE test_db OWNER saurabhd;
postgres=# ALTER USER saurabhd PASSWORD 'spassword'
Evidently, the new user and Database were created from postgres user(default user). \l command showed the following:
Name | Owner | Encoding | Collate | Ctype | Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
postgres | postgres | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 |
template0 | postgres | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
template1 | postgres | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 | =c/postgres +
| | | | | postgres=CTc/postgres
test_db | saurabhd | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 |
As can be seen, the owner name for database test_db is saurabhd. Although, I can still access the DB test_db with 'postgres' user and modify the DB.
Is there a way, I can restrict postgres user(and all other users except saurabhd) from accessing the DB test_db?

Answer 1

ALTER ROLE
The management of roles in PostgreSQL allows different configurations, among them are:
SUPERUSER / NOSUPERUSER. Super User, privileges to create databases
and users.
CREATEDB / NOCREATEDB. Create databases.
CREATEROLE / NOCREATEROLE. Create roles.
CREATEUSER / NOCREATEUSER. Create users.
LOGIN / NOLOGIN. This attribute makes the difference between a role
and a user. Since the user has permissions to access the database
through a client.
PASSWORD. Allows you to change the password.
VALID UNTIL. Expiration of users.
To change the configuration of a user or role we must execute the following command.
ALTE ROLE <nombre del rol> WITH <opciones>
Create a database with a specific user as owner
All databases that we create with a user that has the CREATEDB privileges automatically assign the user as the owner. If what we want to create is a limited user, the way to create it with a specific database will be:
CREATE DATABASE user OWNER saurabhd ;
Assigning super user permissions to a user
The super user license is the highest. With this user you can manage all the objects of the database engine.
To assign this privilege to a role we do it with the following command:
ALTER ROLE saurabhd WITH SUPERUSER;
Assign all permissions to a user to an existing database
When we have just created a user and want to give permissions to an existing database, we can use the following command:
GRANT ALL PRIVILEGES ON DATABASE nameBase TO saurabhd;