Calculate if empty
I am importing information via an ODBC datasource. One field, PERSON_ID, is used to look up and link other information. The problem is this: there are some entries in the original database where the field is blank (depending on whether a person has been validated). This causes me a problem later, and I am wondering if there is a way to define the FileMaker Pro field to automatically generate a PERSON_ID for any instance where the field is empty after the initial import.