The relation Member(StudentId, OrganizationId, RoleId) stores the membership information of student joining organization. For example, ('S1', 'O2', 'R3') indicates that student with Id 'S1' joined the organization with id 'O2' in the role with id 'R3'.
(a) Can StudentId have a null value?
(b) Can OrganizationId have a null value?
(c) Can RoleId have a null value?
(d) It is known that {StudentId, OrganizationId} is a candidate key. What assumption has we made?
Database class.