Deleting Database Roles

A superuser can delete a role with the DROP ROLE statement.

Note that if any user or other role has been assigned the role you are trying to delete, the DROP ROLE statement fails with a dependency message.

=> DROP ROLE administrator;
NOTICE:  User Bob depends on Role administrator
ROLLBACK:  DROP ROLE failed due to dependencies
DETAIL:  Cannot drop Role administrator because other objects depend on it
HINT:  Use DROP ROLE ... CASCADE to remove granted roles from the dependent users/roles

Supply the optional CASCADE parameter to drop the role and its dependencies.

=> DROP ROLE administrator CASCADE;
DROP ROLE