Portal for "Unavailable" Dates

[wavey_d]

I'm trying to create a database to book films and I need to know what exhibition copies are available (i.e. not already booked) to complete the booking. For example, let's say I have only one 35mm print of a film, and it is booked from 12/1-12/4 and 12/7-12/9. If someone requests 12/5-12/6 it would show up in the portal (and therefore available) but if someone requests 12/5-12/7 it would not.

I'm not sure how to make the table with the "booked dates"...or what the (global?) field in the bookings table that is related to it should look like...any ideas on structure and portal relationships to get me started?

Thanks!

David

[comment]

I'm trying to create a database to book films and I need to know what exhibition copies are available (i.e. not already booked) to complete the booking.

Do you have a separate child record for each exhibition copy - or only a quantity field in the Films table?