I have an Access 2007 db that manages school tutors timesheets (see relationship image below).
When inputting timesheets, an admin uses a combobox to select tutors for recording hours worked. However, to prevent any duplicates from occuring, the admins should only see tutors whom do not already have a timesheet entered for the current payperiod (a value we can call currPayPeriod).
For example, an admin inputs timesheets for payperiod 3 and the combobox they use to select the tutor should not show tutors whom have already have a timesheet entered for payperiod 3.
Combobox1 format: ID number, Firstname, Lastname