I understand the importance of providing detailed information on creating roles in Postgres to help those who may be familiar with other database engines. Let’s talk abour how to create role Postgres in this article. When it comes to database management systems, the concept of a “role” in Postgres can indeed be confusing for individuals transitioning from different platforms. Therefore, in the article, it’s essential to articulate the significance of a role within the context of Postgres and to elucidate its functionality in comparison to similar concepts in other database engines.

Explaining the process of creating a role in Postgres and discussing its practical application can effectively demystify this aspect for newcomers. By addressing the nuances and practical examples, the article can serve as a valuable resource for individuals seeking clarity on this topic. This approach aims to bridge the knowledge gap and provide comprehensive guidance on navigating the intricacies of roles in Postgres.

What is a Role?

PostgreSQL simplifies the permission management with one single object: Role. Unlike other database engine permission, users and groups are not different in PostgreSQL. They are considered as role.

Wait? A Permission but That Logins?

Yes.

In the beginning it is a little confusing I know, but after a while, you can understand that it is much simpler than using multiple concepts to manage security and data access.

A Role as Group?

Yes again.

A role can be used as a group. A role can be member of a group (which is another role).

What Does It Solve with a Role?

Database administrators or data architects coming from another database engines are surprised with this terminology in the beginning. But quickly, you can take advantage of this usage.

I don’t like to compare database engines, but most of the database engine has a concept of virtual users, which is managed by the database engine. Some of the database engines using LDAP or operating system as the user registry, in that case engines support client side authentication as well as server side authentication. All of those database engines have role, user, group, permission terminology separately. PostgreSQL simplifies that with a single object: Role.

What is a User?

I think we are fine with definition of a role. To answer how to create role Postges question we need to define our terminology.

What is the purpose of user in all database engines? Managing access to data. In addition, users can log in to database engines. A role manages access to data, and you need a login permission. So here it comes:

A user is a Role with Login permission.

A group is logical sub set of users to manage their permission more efficiently.

How to Create Role in Postgres?

Before diving deeper, please check Postgres’s documentation about roles.

Let’s start with defining a sample role:

CREATE ROLE test_role;

Statement above creates a role named as test_role. Take test_role as a name of set of permissions for now. Let’s see how to delete a role in PostgreSQL:

DROP ROLE test_role;

As you see, dropping an unused role is very simple.

DROP ROLE test_role;

How to Create a User in Postgres?

Let’s create a user in Postgresql, as mentioned above, a user is a role with a login permission, of course, we need to give it a password as well.

CREATE ROLE test_user PASSWORD 'Passw0rd' LOGIN;

Now you can use test_user to login database.

But if you want to run a select query from another schema’s table you will receive an erorr:

Dropping the user is simple as well.

DROP ROLE test_user;

Let’s Create a Group in PostgreSQL

Creating groups are same with roles. You don’t need to add or remove any other parameters. You can directly use groups (roles) to assign to new users:

CREATE ROLE group_role;
CREATE ROLE user_role PASSWORD 'Passw0rd' LOGIN IN GROUP group_role;

user_role is member of group_role. When you grant any permissions to group_role that will be applied to user_role as well.

pg_roles Catalog

Like any other type of object in Postgres, role has it’s own catalog view to. You can use pg_roles view to query roles. But it is not supported to update roles from pg_roles.

pg_auth_members view is the view to store relationships between roles and memberships.

Summary

In this article we talked about roles, how to create a role in Postgres, what is a user, what is group topics.

Database security is a very long section under database management but i tried my best to make this article a great introductory article to permission management.

After exploring the intricacies of roles in PostgreSQL and how to create them, it’s essential to encourage reader engagement. Your comments, questions, and feedback are valuable in enhancing the collective understanding of this topic. Feel free to share your experiences, ask questions about any unclear points, or provide additional insights that could benefit other readers. Your input contributes to the continual improvement and enrichment of our shared knowledge on PostgreSQL and database management. Let’s foster a collaborative learning environment by actively participating in the discussion below.

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