Perform a find for bookings for that day, for that individual, where starttime < 18 and endtime >16. If there is a found set, you have a conflict
You need to have your start and stop times in separate fields for the test to run cleanly. Are you going to be testing against related records for their schedule, for the same date and person?
Please provide a few more details about the structure/relationship between the records you want to compare.
I found this and I like that it doesnt involve any scripting:
"...use Filemaker's native timestamps - if not to actually record the start and stop points, then at least for the calculations?
Once you have that (or even a similar mechanism) in place, set up a self-join relationship as:
Items::StartTS < Items 2::StopTS
Items::StopTS > Items 2::StartTS
Items::ItemID ≠ Items 2::ItemID
If there are any related records in Items 2, they will be overlapping the currently viewed item."
Thats all nice in principal apart from the fact that I dont get it to work at all...
Guess Ill have to follow another helpful advice in that thread: - read the manual