Immediately after any officer of this state whose compensation depends upon or is to be computed by time of service, qualifies to enter upon the discharge of his duties by taking and subscribing the necessary constitutional oath, he shall transmit to the commissioner of administration a true copy of the oath. The commissioner shall cause the date thereof to be recorded in a book which he shall keep for that purpose. The officer's salary shall commence from the date on which the oath is taken.
La. R.S. § 39:341