Basic online store concepts

Regular online store consists of two sections:

• Front end (storefront):
  This is a public part of your system where visitors can browse products catalog, add items to the shopping cart and place orders.
  
• Back end (administrative mode):
  This is a section of your store which should be restricted from public access. Back end provides tools for managing products catalog, view customer orders, configure store settings, etc.

This is how back end and front end interact:

There could be hundreds of ecommerce features supported by a certain online store, but here we shall pay attention only to core facilities required to start selling online:

• Products management
• Shopping cart
• Orders management

These facilities are essential. Every online store should have them implemented at some level, otherwise it would be wrong to call one "online store".
Other facilities, such as customers registration system, credit card processing, shipping quotes with UPS, FedEx and other carriers, discounts, gift certifications and other features are very important, of course, but I would call them "extra", "additional ecommerce features". They help you increase sales once you have already started selling online, but they are not necessary for starting online business.

We will review each of core store facilities one by one. At first we will start from products catalog management, second goes shopping cart engine (the ability to add products to cart) and the third - checkout facility with PayPal Website Payments Standard integration.