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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.