How to Prevent a User to Drop Own Objects???

CREATE OR REPLACE TRIGGER trigger_prevent_drop BEFORE DROP ON DATABASE
BEGIN
IF ora_dict_obj_type = 'VIEW' 
AND ora_dict_obj_owner = 'QO112_1616' 
AND ora_login_user = 'QO112_1616' 
AND ora_dict_obj_name='SAMPLE_NEW'
THEN
raise_application_error (-20000, 'YOU CAN NOT DROP SAMPLE_NEW VIEW!');
END IF;
END;

We will get an erorr message when trying to delete object in my case VIEW