Hi Sylvain,
I am very moved because of your patience with me on my silly question. I have been working with VFP for some months so I don't have much experience about this field. The automatic keys I use for my views are purchase_order_number and invoice_no and so on. Those numbers will appear on the reports for the customers.
I was just worried if the users use my program and they don't know where those numbers come from if they can't start at 1. But I think I go with the suggestions from you, David Stevenson and Larry Miller because by the time the numbers get to the limit of interger number, I don't think I will be able to handle the job any more :):):).
Thank you so much for your help.