Notwithstanding the provisions of article three, chapter six, and article seven, chapter seven of this code, all appointments and promotions of full-time correctional officers, as defined in section two of this article, in the offices of sheriffs of counties of twenty-five thousand population or more, shall be made only according to qualifications and fitness to be ascertained by examinations, which, so far as practicable, shall be competitive, as hereinafter provided. On and after the effective date of this article, no person except a correctional officer appointed as jailer pursuant to the provisions of section two, article eight of this chapter shall be appointed, promoted, reinstated, removed, discharged, suspended or reduced in rank or pay as a full-time correctional officer, as defined in said section two, of any county in the State of West Virginia subject to the provisions hereof, in any manner or by any means other than those prescribed in this article.