Sunday, June 3, 2007

Question 72

When functional dependences maru1.png through maru7.png occur as the attributes of the following relation "order," what is the correct set of attributes for the primary key? For this problem, the notation (A, B) represents the pair of attributes A and B. In addition, the notation A → C represents C's functional dependence on A.

Relation "order" (order_number, order_date, customer_number, customer_name, product_number, product_name, quantity, price)

Functional dependences
maru1.pngorder_number → order_date
maru2.pngorder_number →customer_number
maru3.pngorder_number →customer_name
maru4.pngcustomer_number →customer_name
maru5.png(order_number, product_number) →quantity
maru6.png(order_number, product_number) → price
maru7.pngproduct_number → product_name

a) (order_number)
b) (order_number, customer_number)
c) (order_number, customer_number, product_number)
d) (order_number, product_number)


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