Revoke privileges
You can revoke administrative and object privileges by using the REVOKE command.
When you revoke a privilege from a group, all the members of that group lose the privilege unless they have the privilege from membership in another group or through their user account.
For
example, to revoke the Insert privilege for the group public on the
table films, enter:
SYSTEM.ADMIN(ADMIN)=> REVOKE INSERT ON films FROM PUBLIC;
REVOKE