A customer can register to purchase an item. The customer will provide bank account number and bank: name [can have multiple account number}. After registration, each customer will have a unique customerid. userid and password. A customer can purchase one or more item in different quantities. The items can of different classes based on their prices. Based on the quantity. the price of the item and discount [if any} on the purchased items, the bill will be generated. A bank account is required to settle the hill. The items can be ordered to one or more suppliers