# Fundamentals of Databases assignment

Q.1. Define the following terms:

a) Relational algebra

b) Domain relational calculus

(0.5 Marks)

Q.2. Write the following queries in relational algebra, using the university schema (chapter6):

a) Find the titles of courses in the Comp. Sci. department that have 3 credits.

b) Find the highest salary of any instructor.

(0.5 Marks)

Q.3. Let the following relation schemas be given:

R = (A, B,C) and S = (D, E, F)

Let relations r(R) and s(S) be given. Give an expression in the tuple relational calculus that is

equivalent to each of the following:

a) ïƒ• A(r )

b) ï³ B =17 (r )

(0.5 Marks)

Q.4. Use Armstrongâ€™s axioms to prove the soundness of the pseudo transitivity rule.

If Î± â†’ Î² and Î³ Î² â†’ Î´, then Î± Î³ â†’ Î´.

(1 Mark)

Q.5. Compute the closure of the following set F of functional dependencies for relation schema r

(A, B, C, D, E).

Aâ†’BC

CDâ†’E

Bâ†’D

Eâ†’A

(NOTE: list at least 6 members of F+)

(1 Mark)

Q.6. List two benefits of normalization

(0.5 Marks)

Q.7. Find candidate keys for the relation R(ABCD) having following FDâ€™s

ABâ†’CD, Câ†’A, Dâ†’A

(1 Mark)

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**Category**: Sample Questions