Create a UML class diagram for Quadrex consistent with the REA ontology. Quadrex Computers is a company that buys computer components, assembles the components into computers, and then sells the computers at high prices. Each computer is assigned a unique identification number, and computers that have common configurations are categorized into types (laptop, desktop, etc.). Categories can be entered into the dataset before any computers in the categories are actually assembled.
All sales are handled via mail or e-mail, as Quadrex does not have any showrooms. The company assigns a salesperson to each of its large corporate customers and the salesperson takes sample computers to these customer locations to demonstrate features as part of their sales calls. Only a small percentage of Quadrex’s sales calls result in orders, and sometimes a salesperson might need to make several sales calls to the same customer to obtain one order from that customer. If a sales call results in many subsequent orders, Quadrex only keeps track of the first sales order. Orders also result from customers surfing the Internet and seeing descriptions of the computers on the company website. These customers are not assigned to specific salespeople; the company only tracks the salesperson that actually took the order (or physically manages online orders). Some of Quadrex’s salespeople are hired to handle just such orders and as such are not assigned specifically to any customers.
If a customer orders multiple computers on one sale order and some of the computers are immediately available whereas the others are not yet assembled, the company ships the available computers right away and then ships the remainder of the order when the rest of the computers are assembled. Sometimes Quadrex combines computers from multiple sales orders into a single shipment. A shipping clerk handles each shipment. Customers can pay for multiple sales with a single payment, but no partial payments are accepted. Each sale transaction is tracked by a shipment ID. An invoice is sent to the customer and payment is due within 10 days. All sales are final. The company receives cash from other activities. Employees and customers need to be entered into the database before any transactions involving them occur (including assignments).
Attributes:
Salesperson ID (Sp-ID#)
Location of Cash account (Ca-loc)
Cash Account Number (Ca #)
Computer Category ID # (Cat ID#)
Salesperson name (Sp-name)
Cashier name (Cash-name)
Shipping clerk ID (SC-ID#)
Cashier ID (Cashier ID#)
Sale Order ID (SO-#)
Shipment ID (Ship ID#)
Date of sales call (SC-date)
Sales Call ID (SC-ID)
Cash Receipt ID (CR-ID)
Date of cash receipt (CR-Date)
Shipping clerk name (SC Name)
Name of customer (Cust-Name)
Total sale dollar amount (Sale-Amt)
Date of Sale Order (SO-Date)
Dollar amount of cash receipt (CR-Amt)
Current balance of cash account (AcctBal)
Shipping address for a customer (Cust-Ship)
Date of shipment of computers (Ship-Date)
Description of computer category (Cat-Desc)
Identification number for a finished computer (CompuID)
Proposed selling price for a type of computer on a sales call (prop-SP)
Suggested selling price for a computer category (List-Price)
Quoted selling price for each item on a sale order (Ord-SP)
Actual selling price for a particular finished computer (Act-SP)
Customer ID # (Cust-ID)
Computer assembly date (Assemb Date)