It depends a lot on what kind of logic you want to put in the program. Do you want to prevent that a person can be put into two overlapping shifts? Say, employee A starts at 9 AM on Monday, and on 12 AM on Monday? Or to prevent being assigned at a shift starting at 9 PM on Monday, and a shift starting at 3 AM on Tuesday? Is there a minimum time between shifts to be taken care of? Holidays? Vacation time? Checks whether there are always at least N people working, and at most M? Or is it ok if all 20 start the same shift? Or is your program just a dumb front-end to a single, simple table in the database?

Abigail