Auto Populate with Unique ID
I have a field that auto populates with a serial unique ID number. I have it populate upon committing the record, so that if users create new records but don't save them, the field doesn't add a new number. Now, I would like to be able to have users input a unique ID number with a dash (such as 7123-100), and thus overriding the auto populate function. Otherwise, when the next person comes to add a new record, there is a "wasted" number. Is there a way to make filemaker only autopopulate that field with the next sequential number if it is left blank?