Well, I was thinking I was using row buffering on that form, but it turns out I was using table buffering. The uniqueness error was correct. I populated the field with a duplicate value. However, as I mentioned, that's not actually a problem until you execute a TABLEUPDATE. The help file says "If the cursor uses table buffering, then the modified current record is saved into the buffer." The operative phrase here is "into the buffer." So if it's only saved into the buffer, why did I get the uniqueness error? I fixed the problem by simply ensuring the value is unique, but it left me wondering. This feature is not working like it seems it should be working.

>Hi Russell,
>
>> What's the real answer here?
>
>Use table buffering. Row buffering is something that VFP simulates behind the scenes with all kind of exceptional code. Table buffering is VFP's native buffering. There is no reason to use row buffering, unless the program doesn't care when data is written and buffering is just there as a little convenience for the user. But then you wouldn't be asking if VFP updates data or not...