Modify Exercise 24.4 to provide a ComboBox and a TextArea to allow the user to perform a query that is either selected from the ComboBox or input into the TextArea. Sample predefined queries should include:

a) Select all employees working in department SALES.

b) Select hourly employees working over 30 hours.

c) Select all commission employees in descending order of the commission rate.

Exercise 24.4

We introduced an employee-payroll hierarchy to calculate each employee’s payroll. In this exercise, we provide a database of employees that corresponds to the employee-payroll hierarchy. A SQL script to create the Employees database is provided with the examples for this chapter. Figure 24.35 is the entity-relationship diagram for the employees database.

Fig. 24.35

salaried Employees social SecurityNumber weeklySalary bonus hourlyEmployees social SecurityNumber hours wage bonus employees social SecurityNumber firstName lastName birthday employee Type departmentName commission Employees social SecurityNumber gross Sales commissionRate bonus basePluscommission Employees social SecurityNumber grossSales commissionRate baseSalary bonus