Originally Posted by Tuork
Hmm.. this could work. The only thing I'm worried about is what to do when something isn't exactly half an hour.
I guess I would have to manage 30 minute time slots, but that would mean a lot of records on the "free periods" table.
Oh, and thanks for your help!
Why does it need to be 30 minute intervals? Use a time field and you can set it to hours and minutes.