DB Override

I have a coupon website that accepts national and local coupons. - local coupons take data from 2 tables: (1) coupon info from COUPON table and (2) location data from associated STORE table. - The local SEARCH and the local NEWSLETTER is based on coupon location in STORE table. * The problem is the location of EVERY coupon is based upon the store location. HERE IS TASK: - Add country, city & state fields to COUPON form - So each coupon has its own location - make GEO search use this field 1st. If NO data here then use STORE location by default - make newsletter coupon import use this field 1st. If NO data here then use STORE location by default