4.1.6 The information about children can be ascertained from motherOf and
fatherOf relationships. Attribute ssNo is required since names are not unique.
4.1.7
4.1.8 a)
(b)
4.1.9
Assumptions
A Professor only works in at most one department. A course has at most one TA.
A course is only taught by one professor and offered by one department. Students and professors have been assigned unique email ids.
A course is uniquely identified by the course no, section no, and semester (e.g. cs157-3 spring 09).
4.1.10
Given that for each movie, a unique studio exists that produces the movie. Each star is contracted to at most one studio.
But stars could be unemployed at a given time. Thus the four-way relationship in fig 4.6 can be easily into converted equivalent relationships.