theres a customer table(pk is ebay_id) and a cellphone table (pk cellphone_id). there is also a payment table.
so the payment table records the customer who purchases a phone(ebay_id) and the cellphone_id, the cc# they used and the amount of the purchase.
i want the primary key to be composite because the buyer might buy more than one phone, so it needs the cellphone_Id to be unique. and i have the cc# on there just to have more data when i run queries.