Field validation unique week of Fiscal Year based on userID
I am trying to create a database that creates a weekly record with information gathered on a weekly basis. So far I have created 2 tables. One contains the clients information and the second contains weekly report information. The tables are linked via a unique userID field. I want to have the data entry person select a day of week and have the week of fiscal year atuomatically calculated, this part i have figured out. What I need help with is a way to validate that the selected date does not create a new record for an existing week of fiscal year based on that usersID. If I need to be more clear please ask. If I need to setup the database differently please advise....