noob sql questions

as an intermediate noob i would only use 1. the "more efficient" thing sounds bogus

We're on SQL Server 2005 but I can't imagine it's any different there.

I got my thing to work ^________^

batch file

echo off
Set objShell = CreateObject("Wscript.Shell")
Echo Please enter password and press return
Set /p var1=
osql -d AFW3 -U sa -P password -S TESTSERVER -q "Exec EmployeePasswordLogout @LoginPassword=%var1%"

sql stored proc

CREATE PROC EmployeePasswordLogout (@LoginPassword varchar (10))
As
Update tblEmployee
set LoginDateTime = null
where @LoginPassword = LoginPassword
GO

Dude seriously

Also what happens if 2 employees by coincidence have the same password?

Being logged out while you are still using the database is only a problem if you were to try to enter it again which is pretty rare. But it probably isn't too hard to get username in there too.