Question

Exercise 4

Determine whether or not the following Σ11 and Σ12 are equivalent. Show and explain your answer

R1= {A, B, C}, Σ11 = {A->B, A->C, C->A} and Σ12 = {A->B, AB->C, A->C, C->A} on R1, respectively.

Exercise 5

Decompose the following into BCNF R = (A, B, C) F = {A → B, B → C}

Exercise 6

George withdraws $100 from his account (T1) while Mary deposits$500 into George’s account (T2) in the following transaction process.

Draw up the steps with equivalent transactions and then explain what the problem is what the process.

T1: SELECT balance FROM Account WHERE name=’George’;

T1: UPDATE Account SET balance=balance-100 WHERE name=’George’;

T2: SELECT balance FROM Account WHERE name=’George’;

T1: ROLLBACK;

T2: UPDATE Account SET balance=balance+500 WHERE name=’George’;

T2: COMMIT;

Exercise 7

TRANSPORTONE is a newly established company on transportation network in Australia.

Consider the relation schema ORDER={Customer, Date, OrderID, Employee, Manager}and the

following set Σ of FDs:

Fd1:{Customer, Date}→{OrderID}

Fd2:{Employee}→{Manager
}

Fd3:{OrderID, Date}→{Customer, Employee}

Fd4:{Date}→{Manager}

1.Normalize into BCNF

2.Normalize into 3NF

3.An order can be identified using the customer who submitted the order and date of submission of the order. Write down the functional dependency.

Answer 1

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