Use your calculation expression that combines first and last names, but use it on a text field as an auto-enter calculation. You can probably just change your calculation field to Text and then go into Field Options, select the auto-enter calculation option and find that your original expression now appears as the auto-enter calculation. Be sure to clear the "do not replace existing value..." check box.
Since this is a text field, you can then specify the unique values validation field option.
Hi Phil, thanks for getting back.
I'm afraid it's not working, unless I'm doing it wrong. My "full name" calc field does have text selected as output format. However I don't have any field options for validation, just the specify calc window and from there storage options. Or did you mean I should covert the type of field from calc to text? But then I lose the calculation (??). I'm in manage database by the way, in case I'm looking in the wrong place...
To repeat, you must change your field TYPE from Calculation to Text, then open field options and select the Calculation option on the Auto-Enter tab.
Find your field in Manage | Database | Fields
Select the field by clicking it.
Use the Type drop down at the bottom right to change your field type from calculation to text.
Double click the field definition or click the options button.
Select the Auto-Enter tab
Select the calculation option
Got it (finally)! Your directions were clear, but not having had any professional training I need the extra detailed spelling out... Thanks for your help, Phil!