DB backend for nurse scheduling problem

Question

I'm taking a Software Design course at Penn State and my group is tasked with solving the Nurse Scheduling Problem. I would like to have it store previous schedules as well as the current schedule in a MySQL database, but I'm not sure what the best way to do this is.

For the current schedule, I was thinking of a table with the date, the shift and employeeID for any days an employee is working. But when I generate a new schedule, what do I do with that schedule? Do I have an archive table with a similar layout that I copy the schedule into before emptying the table, or do I generate an XML file of that schedule and archive it in the database?

Any suggestions?