DBMS & SQL Mock Test #2: Normalization, Candidate Keys & SQL Queries

Question 1 of 5 Correct: +2 | Negative: -0.5

A relation R(A, B, C, D) is in 3NF if for every non-trivial Functional Dependency X -> Y:

A X must always be a Super Key B Either X is a Super Key OR Y is a Prime Attribute C Y must be a Non-Prime Attribute D No transitive dependency of Prime attributes exists

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Question 2 of 5 Correct: +2 | Negative: -0.5

What will be the output of the following SQL query on a table Employee(id, bonus) containing 4 rows with bonus values: 100, 200, NULL, 300?

SELECT COUNT(*), COUNT(bonus), AVG(bonus) FROM Employee;

A 4, 4, 150 B 4, 3, 200 C 3, 3, 200 D 4, 3, 150

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Question 3 of 5 Correct: +2 | Negative: -0.5

Which SQL keyword is used to filter groups created by the GROUP BY clause based on an aggregate condition?

A WHERE B HAVING C ORDER BY D FILTER

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Question 4 of 5 Correct: +2 | Negative: -0.5

In database transaction management, which property of ACID ensures that either all operations of a transaction are reflected properly in the database or none are?

A Atomicity B Consistency C Isolation D Durability

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Question 5 of 5 Correct: +2 | Negative: -0.5

Every relation that has only two attributes (e.g., R(A, B)) is ALWAYS in:

A Only 1NF B Up to 2NF only C Up to 3NF only D BCNF (Boyce-Codd Normal Form)

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