Maybe you could create a cursor with the same key as your table, and link it to the table with SET RELATION.

>Hi Everybody,
>
>I edit a table in a grid. Is there a way that I could add a field to this table virtually? I don’t want to physically change the user’s tables. The names of the fields are uncertain and we don’t know whether there is a unique field in the table. This field will be used for programming usages.
>
>Thank you,
>Ali