Let Ai , 1 %u2264 i %u2264 5, be the domains for a table D %u2286 A 1 X A 2 X A

ID: 3341512 • Letter: L

Question

Let Ai , 1 %u2264 i %u2264 5, be the domains for a table D %u2286 A1 X

A2 X A3 X A4 X A5, where A1 = {1, 2} (used to identify the

daily vitamin capsule produced by two pharmaceutical companies),

A2 = {A, D, E}, and A3 = A4 = A5 = Z+. The table D

is given as Table 5.8.

a) What is the degree of the table?

b) What is the projection of D on A1 X A2? on A3 X

A4 X A5?

c) This table has no primary key. (See Exercise 13.) We

can, however, define a composite primary key as the cross

product of a minimal number of domains of the table, whose

components, taken collectively, uniquely identify each list

of D. Determine some composite primary keys for this

table.

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