title: store mutiple values in php session
body: <p>I am writing a script in php, which is quite similar to a shopping cart. what i want to do is when a users adds a certain product i need to add the productid to a session variable,without storing in a database. so each time the user adds a product the productid needs to be stored in a session variable.</p>
  
  <p>and when the user checkouts i need to retrieve all the productids and display?</p>
  
  <p>can some one please explain me how to do it? coz im fine with 1 product but not sure how to store and retrieve multiple values.</p>
  
  <p>any help will be much appreciated</p>