We see this in new construction from time to time but does have requirements. It must be treated as a roof. It would have a slope of 1/4" per ft and like a roof the flashing should go up the wall I think 6". That creates a few problems like there should be a 6" step down from the door and the bottom of the siding has to be removed and replace after. The deck is usually covered with vinyl deck membrane which is wrapped up the wall and up the post.
The cheat for this house would be to lower the floor to be aprox. level with or just above the top of the foundation or the required 6" and the deck plywood carry out 1 or 2" past the foundation so the membrane can be done without removing the siding. Then a flash would be slipped up under the siding and a decritive board would be added below that and the post would be dressed out.
Best if the level of the floor is 1 1/2" above the foundation as just like any other roof there has to be venting above the insulation and below the sheeting.
We have done this to a few old houses and it does pass inspection.