A company has only three types of employees: part-time, full-time, and consultants, each with the following attributes: Part-time employees: EmpID, Name, DateJoined, HourlyRate Full-time employees: EmpID, Name, DateJoined, Salary, JobCode Consultants: EmpID, Name, DateJoined , ConRate, SkillCode Each employee in this company belongs to exactly one of the three types. To model this business situation, you need to use enhanced E-R diagram. Answer the following questions related to design an enhanced E-R diagram.

1. Which entity should be modeled as the supertype entity? Which entities should be modeled as the subtype entities?

2. What attributes should the super type entity have in the enhanced E-R diagram?

3. What disjointness constraint does the supertype/subtype relationship use? How do you interpret this constraint?

4. What completeness constraint does the supertype/subtype relationship use? How do you interpret this constraint?