This week, we learned enhanced entity relationship diagram (EERD). There are two types of constraints between the super and sub types. They are disjointness and completeness constraints. Answer these questions, given this EERD:

1. Is it required that every entity instance in the STUDENT table be associated with an entity instance in the UNDERGRADUATE table or GRADUATE table? Why or why not?
2. Is it possible for an undergraduate student to appear in the UNDERGRADUATE table without appearing in the STUDENT table? Why or why not?

Student PK Studentid FirstName LastName Address Student Type d Undergraduate Graduate PK Studentld PK Studentid ACTScore GREScore Student PK Studentid FirstName LastName Address Student Type d Undergraduate Graduate PK Studentld PK Studentid ACTScore GREScore