Hi Team,
    I want to create a e-commerce shopping cart website using force.com. I am thinking about the standard salesforce objects for my database architeture. Those are Accounts, Contact, Contract, Products, PriceBook, Attachment & Document, Opprtunities etc. Could you please guide me to build this? I have created a basic ER- digram for a normal shopping cart, but I have no idea about what salesforce objects can use insted of my entity. Dou you have any shopping cart ER-Diagrmas related to salesforce. Otherwise Please tell me the sfdc object relations. I am not looking for any external  applications  on app exchange for now.

Please chek the ER diagram for shopping cart :  http://creately.com/diagram/hjs63tgx1/A4lBATFQ0CuG88bdEUMDzPrXc=