Rental System

[cfalab]

Hi, I'd appreciate any help or pointers I can get for this project.

Basically, my office has three multimedia projectors to loan out to faculty, and we want to make the rental system with Filemaker.

So I've created web forms and everything to enter name, date, and stuff like that - but now I need to figure out how to take care of date conflicts.

My problem is that I need to make the system so that only 3 projectors can be checked out per day. So that if someone tries to enter a reservation and they are the 4th rental on that day, Filemaker will not validate and I can set up an error message.

Right now I have 1 basic field called Projector Conflict. I want Projector Conflict to come up as "1" if it is the first reservation on a given day, "2" if it is the second, and "3" if it is the 3rd.

So basically upon creation, I need Filemaker to check other records on a given day and report back with how many other reservations there are already.

For example, if 4/30 has 2 reservations already, I want Projector Conflict to enter "3" the next time someone makes a reservation for 4/30.

Any ideas on where to start?

[comment]

Define a self-join based on date - then you can make you field a calculation =

Count ( Reservations 2::Date )