How to Change User to Superuser in PostgreSQL

Name

Antonio Di Nicola

Published on 5/13/2022

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PostgreSQL is a powerful open-source database management system that allows multiple users to access and manipulate the data. Each user in PostgreSQL has different permissions and roles assigned to them, based on their level of access and authority.

In this tutorial, we will learn how to change a user's permissions and assign the superuser role in PostgreSQL. We will go through the process step-by-step and provide code examples for each step.

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Create a New User

Before we can change a user's permissions in PostgreSQL, we need to create a user first. To create a new user, we can use the CREATE USER command followed by the username and password.

CREATE USER newuser WITH PASSWORD 'password';

This command will create a new user called newuser with the password password.

View Existing User Permissions

To view the current permissions and roles assigned to a user in PostgreSQL, we can use the \du command in the psql console. This command will display a list of all the current users in the database, along with their roles and permissions.

\du

This command will show a list of all the current users, their roles, and whether they are a superuser or not.

Alter Existing User Permissions

To change a user's permissions in PostgreSQL, we can use the ALTER USER command followed by the username and the new permission or role.

For example, if we want to grant the newuser the permission to create a database, we can use the following command:

ALTER USER newuser CREATEDB;

This command will grant the newuser the CREATEDB permission, allowing them to create a database.

We can also revoke a permission from a user by using the ALTER USER command with the REVOKE keyword. For example, to revoke the CREATEDB permission from the newuser, we can use the following command:

ALTER USER newuser REVOKE CREATEDB;

This command will revoke the CREATEDB permission from the newuser, preventing them from creating a database.

Assign Superuser Permission

A superuser in PostgreSQL has all the permissions and roles assigned to them, allowing them to perform any action on the database. To assign the superuser role to a user, we can use the ALTER USER command with the SUPERUSER keyword.

For example, to assign the superuser role to the newuser, we can use the following command:

ALTER USER newuser SUPERUSER;

This command will assign the newuser the superuser role, giving them all permissions and roles in the database.

Revoke Superuser Permission

To revoke the superuser role from a user in PostgreSQL, we can use the ALTER USER command with the NOSUPERUSER keyword.

For example, to revoke the superuser role from the newuser, we can use the following command:

ALTER USER newuser NOSUPERUSER;

This command will revoke the superuser role from the newuser, removing all the permissions and roles assigned to them.

Conclusion

In this tutorial, we learned how to change a user's permissions and assign the superuser role in PostgreSQL. We went through the process step-by-step and provided code examples for each step, making it easy to follow along.

Remember to always be careful when changing user permissions in PostgreSQL, as it can have a big impact on the database. With that said, the ALTER USER command is a powerful tool that allows you to customize the level of access and authority for each user in the database.