There are another user modify the record please wait problem

Question

Hi guys i have problem

I have table Employee have two fiels

EmployeeID

EmployeeName

And i have two useres A,B

User A changes  EmployeeName from michel to morinio when EmployeeID=5

User B need to change EmployeeName from michel to polo when EmployeeID=5

so that it must have message error tell him please wait there are another user changes in EmployeeID =5

this is exactly what i need

i need to do that using timestamp data type

how i do that