Im studying about software architecture. And i would like to build a physical view for a basic online web store where there are users that sell products, others that buy products and others that just browse the site.

Im doing like this,but I dont know if its correct, it seems very basic. Do you know what should be added so the diagram can be more complete? Or its ok?

The example is just a basic store that has use cases like:

Seller: create products, edit products, list products, remove products, search products, list buyers, notify buyers, search buyers  buyers: place order, download invoice, contact seller, add comments  Users: browse the site create account, login, logout, edit user profile