You appear to have two tables with a portal from on to the other.
Perhaps: Students::StudentID = Attendance::StudentID?
Do you create a new record in this portal each time you mark attendance for a new day?
If you are creating a new record in the portal each time, you can set up a field to auto-enter the creation date to automatically log the current date each time you log a student's attendance in this manner.
But that assumes a design you may or may not have here...