Database roles are conceptually completely separate from operating system users. In practice it might be convenient to maintain a correspondence, but this is not required.

Because roles can own database objects and can hold privileges to access other objects, dropping a role is often not just a matter of a quick

Functions and triggers allow users to insert code into the backend server that other users might execute unintentionally. Hence, both mechanisms permit users to "Trojan

A database role can have a number of attributes that define its privileges and interact with the client authentication system.

PostgreSQL provides a set of default roles which provide access to certain, commonly needed, privileged capabilities and information. Administrators

It is frequently convenient to group users together to ease management of privileges: that way, privileges can be granted to, or revoked from, a group as a whole. In