InfoPath Dev

Thanks for your quick response. Could you be more specific for setting the field using rules or code. Appreciate that.    

Senario as below, In the back-end database there are three tables associated with this question:  1.        The table [Promotions] (which has a primary key on the field [Promotion_ID])   …this table links by the field [Promotion_ID] to the table…  2.       ...