making a calc field unique?

[anna f]

I have a patient info db in FMP 5.5. Firstname, lastname, and a calc field for wholename. I want the user to get some sort of message if s/he enters a patient twice. I can't seem to figure out how to validate a calculation field as having to be unique. I tried a text field with autoenter data (wholename) validating it as unique but that doesn't work. You need to actually enter something in the field to make it validate. It isn't really practical to script it (although I wrote one that works) unless I can trigger the script upon exiting a field. Even then, the user must tab out of the "comparison" field. Double entries are a nightmare for us. Any suggestions?

[comment]

Define a self-join relationship "SameName":

wholename = ::wholename

Validate lastname (by calculation, validate always) =

not Count( SameName::PatientID )

[anna f]

Thank you- this does work upon "commital" of the record. Too bad we can't do "floating" value lists. That would be cool.

[comment]

It should work like any other field validation. Make sure that wholename is a calc field (not auto-enter), and try checking "Validate only if field has been modified".