Question

Given the following business scenario, create a Crow’s Foot ERD using a specialization hierarchy if appropriate. Granite Sales Company keeps information on employeesand the department that they work in. For each department, the department name, internal mail box number, and office phone extension are kept. A department can havemany assigned employees, and each employee is assigned to only one department. Employees can salaried employees, hourly employees, or contract employees. All employeesare assigned an employee number. This is kept along with the employee’s name and address. For hourly employees, hourly wage and target weekly work hours are stored(e.g., the company may target 40 hours/week for some, 32 hours/week for others, and 20 hours/week for others). Some salaried employees are salespeople who can earn acommission in addition to their base salary. For all salaried employees, the yearly salary amount is recorded in the system. For salespeople their commissionpercentage on sales and commission percentage on profit are stored in the system. For example, John is a salesperson with a base salary of $50,000 per year plus 2%commission on the sales price for all sales he makes, plus another 5% of the profit on each of those sales. For contract employees, beginning date and end date oftheir contract are stored along with the billing rate for their hours.

Answer 1

CROW FOOT NOTATION

Crow Foot Notation Employee Department PK employeeNo PK Department No Em ployee_Name Department_Name Employee_Contact Employee_Address Depratment No nternal_MailBox Te lephone_Extension FK dDistinct Hourly based Salary based Contract Based Contract Basis Hourly Basis Salary Basis employeeN o PK FK employeeNo PK FK employeeNo PK FK Emp_Hourly_wages Emp_Salary Account Emp Contract_Start_Date Emp Hourly Targets Emp_Sales_Salaries Emp_Contract _End_Date Emp_Contract Amount 0 Overlapping Sales Wages Sales Person EmployeeNo sales_percentage comm ission

From the above Crow Foot Notation, the relationship between Super class and Sub class is shown clearly, i.e

Employee is super class, and the different types of employees are represented by specialization of three types, there are Salary, Hourly and Contract based. Again the Salary based employee is super class of Sales Employee, representing partially participation.

From the above notation, "d" represents distinct i.e distinct employees of type Salary, Hourly and contract.

And "O" represents, Overlapped, means same object is aggregating two specific outcomes which are overlapped.

They arre Salary based and Sale wages based employee.