Hi, I'm currently creating an application which involves selling of products, equipment and service repair, also rentals of equipment. What is the best database design in this application? currently I have tables for Customer, Invoice, InvoiceDetail, ProductList, EquipmentList, WorkOrder. Do I need to have separate invoice table for rentals which is recurring invoice. and also do I need to create 3 separate create invoice form for selling parts, selling equipment and rental of equipment, because of parts lookup or equipment lookup for description. the system should prompt to create invoice every month which specifies covered dates. I'm using VB2010 and MS Access, Thanks so much for any help