Payroll: Use Case and Employee

Problem Statement
As the head of Information Technology at Acme, Inc., you are tasked with building a new payroll system to replace the existing system which is hopelessly out of date. Acme needs a new system to allow employees to record time card information electronically and automatically generate paychecks based on the number of hours worked and total amount of sales (for commissioned employees). The new system will be state of the art and will have a Windows-based desktop interface to allow employees to enter timecard information, enter purchase orders, change employee preferences (such as payment method), and create various reports. The system will run on individual employee desktops throughout the entire company. For reasons of security and auditing, employees can only access and edit their own time cards and purchase orders. The system will retain information on all employees in the company (Acme currently has around 5,000 employees world-wide). The system must pay each employee the correct amount, on time, by the method that they specify (see possible payment methods described later). Acme, for cost reasons, does not want to replace one of their legacy databases, the Project Management Database, which contains all information regarding projects and charge numbers. The new system must work with the existing Project Management Database, which is a DB2 database running on an IBM mainframe. The Payroll System will access but not update information stored in the Project Management Database. Some employees work by the hour and they are paid an hourly rate. They submit timecards that record the date and number of hours worked for a particular charge number. If someone works for more than 8 hours, Acme pays them 1.5 times their normal rate for those extra hours. Hourly workers are paid every Friday. Some employees are paid a flat salary. Even though they are paid a flat salary, they submit timecards that record the date and hours worked. This is so the system can