Saving before quiting and loading when joining

[JanKy]

Hello, and sorry for asking so many questions. ( Yeah, i feel bad for making so many mistakes )

But i am trying to save a player's team name and rank in that team, before quiting, and load it back up when he joins.

Here's my try : 

function saveBeforeQuit ()
	oldTeam = getElementData(thePlayer,"gang");
	idkrang = getElementData(thePlayer,"gang_leader");
end
addEventHandler ( "onPlayerQuit", root, saveBeforeQuit)

function loadOnJoin ()
	if oldTeam ~= "None" and getElementData(thePlayer,"gang") ~= "None" then
		setElementData(thePlayer,"gang",oldTeam)
		setElementData(thePlayer,"gang_leader",idkrang)
	else
		setElementData(thePlayer,"gang","None")
		setElementData(thePlayer,"gang_leader","not")
	end
end
addEventHandler ( "onPlayerJoin", getRootElement(), loadOnJoin )

( Where "gang_leader" stands for the rank )

And i get the following errors :

Bad argument @ 'getElementData' [Expected element at argument 1, got nil]
Bad argument @ 'setElementData' [Expected element at argument 1, got nil]
Bad argument @ 'setElementData' [Expected element at argument 1, got nil]

I tried adding "source" instead of "thePlayer" but in that case, whenever a player joins, their team is set to the player that left before.

[Abdul KariM]

use 

accountData or sql

[JanKy]

Oh, damn, thank you ^^. Here's how i did it.

function onPlayerQuit ( )
	local playeraccount = getPlayerAccount(source)
	setAccountData ( playeraccount, "dayzteam", getElementData(source,"gang") )
	setAccountData ( playeraccount, "dayzrank", getElementData(source,"gang_leader") )
end
 
function onPlayerLogin (_, playeraccount )
	if ( playeraccount ) then
		local oldTeam = getAccountData ( playeraccount, "dayzteam")
		local oldRank = getAccountData ( playeraccount, "dayzrank")  
		setElementData(source,"gang",oldTeam)
		setElementData(source,"gang_leader",oldRank)
	end
end
 
addEventHandler ( "onPlayerQuit", getRootElement ( ), onPlayerQuit )
addEventHandler ( "onPlayerLogin", getRootElement ( ), onPlayerLogin )