>Jim,
>
>You gave me the following code:
>
>* control's valid
>IF EMPTY( THIS.Value )
> THIS.Value = .NULL.
>ENDIF
>
>This works for character and memo datatypes but I can't get it to work for numerics. When I type in a 0 (zero) and tab out it becomes NULL.
>
>Can you help?

The problem is that 0 is the defined EMPTY() value for a numeric field, and in this case, EMPTY() and ISNULL() do not mean the same things. You'll have the same problem with logicals, where .F. is empty but not null, and with dates, where {} is empty but not null. You might try changing the first line of Jim's code fragment to:

IF VARTYPE(this.Value) = 'C' AND EMPTY(this.Value)

since both memo fields and strings will return "C"