Question $2$: $[20$ Marks$]$

Assume your company is developing a generic digital camera online purchasing system that can be sold

to different camera stores. An initial analysis phase of the project has resulted in the following informal

description of relevant data for the system.

A store will be selling a variety of digital cameras and lenses. The digital cameras can have following

mutually exclusive optional features:

$1.$ An ability to replace lenses.

$2.$ Cameras with an electronic viewfinder.

$3.$ Cameras with an optical viewfinder.

$4.$ Cameras with an optical rangefinder.

Relevant properties of all cameras are the model number, retail price and the number currently in stock.

Additionally, for cameras without an ability to replace lenses there is focal length range.

Cameras with an ability to replace lenses are related to one or more lenses.

Properties of a lens that are relevant include the model number, retail price and the number currently in

stock.

Customers are either domestic customers or foreign customers. Properties of customers that are relevant

include a unique customer number, a customer name, an email address and a shipping address.

Each customer may have any number of purchase orders. Each purchase order is for only one unit of any

product at a time, either a camera or a lens, and will also have a selling price that may be different from

the retail price of that item.

Draw an ER$/$EER schema diagram for this application and upload it to your submission on Crowdmark.

Discuss any assumptions you make, and then justify your ER$/$EER design choices. You must not add any

additional attributes or data requirements, strictly limit your diagram to the description given.

PLEASE CHECK IF THE ER DIAGRAM I HAVE PROVIDED IN PICTURE IS CORRECT FOR THE QUESTION PROVIDED OR NOT. AND PLEASE JUSTIFY WHAT ASSUMPTIONS WERE MADE AND EXPLAIN THE ER DIAGRAM IN THE PICTURE PROVIDED AS MUCH AS POSSIBLE.