10 Normal form identifying MCQ

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10 multiple-choice questions related to identifying the normal form of a table based on given functional dependencies, useful for UGC NET, SET, GATE, ISRO, and other competitive exams. 

Question 1: 1NF Identification

Q1: A table with the following structure is given:

  • Attributes: {A, B, C}

  • Functional Dependencies: A → B, A → C

Does this table meet the requirements of 1NF?

  • A) Yes, because all attributes are atomic

  • B) No, because there are partial dependencies

  • C) Yes, because there are no repeating groups

  • D) No, because it violates 3NF

Answer: A) Yes, because all attributes are atomic

Explanation: A table is in 1NF if all its attributes contain atomic values and there are no repeating groups. The given table does not have any repeating groups or multi-valued attributes, so it satisfies the criteria of 1NF.

Question 2: 2NF Identification

Q2: A table with the following structure is given:

  • Attributes: {A, B, C}

  • Functional Dependencies: A → B, A → C

Is this table in 2NF?

  • A) Yes, because there are no partial dependencies

  • B) No, because it violates 1NF

  • C) Yes, because it is in 1NF and has no partial dependencies

  • D) No, because there are transitive dependencies

Answer: C) Yes, because it is in 1NF and has no partial dependencies

Explanation: A table is in 2NF if it is in 1NF and has no partial dependencies. Since A is the only key in this table, there cannot be any partial dependencies (which occur when a non-key attribute depends on part of a composite key). Thus, this table is in 2NF.

Question 3: 3NF Identification

Q3: A table with the following structure is given:

  • Attributes: {A, B, C}

  • Functional Dependencies: A → B, B → C

Is this table in 3NF?

  • A) Yes, because there are no partial dependencies

  • B) No, because there are transitive dependencies

  • C) Yes, because it is in 2NF

  • D) No, because it violates 1NF

Answer: B) No, because there are transitive dependencies

Explanation: A table is in 3NF if it is in 2NF and does not have transitive dependencies. Here, A → B and B → C imply that A → C indirectly through B. Since C is not fully dependent on A directly, this is a transitive dependency, violating 3NF.

Question 4: BCNF Identification

Q4: A table with the following structure is given:

  • Attributes: {A, B, C, D}

  • Functional Dependencies: AB → C, C → D

Is this table in BCNF?

  • A) Yes, because every determinant is a candidate key

  • B) No, because there are partial dependencies

  • C) No, because C is not a candidate key

  • D) Yes, because it is in 3NF

Answer: C) No, because C is not a candidate key

Explanation: A table is in BCNF if it is in 3NF and every determinant (an attribute that functionally determines other attributes) is a candidate key. Since C → D and C is not a candidate key, this table is not in BCNF.

Question 5: 4NF Identification

Q5: A table with the following structure is given:

  • Attributes: {A, B, C}

  • Functional Dependencies: A → B, A → C, B ↔ C

Is this table in 4NF?

  • A) Yes, because there are no multi-valued dependencies

  • B) No, because it is not in BCNF

  • C) No, because B ↔ C is a multi-valued dependency

  • D) Yes, because it is in BCNF

Answer: C) No, because B ↔ C is a multi-valued dependency

Explanation: A table is in 4NF if it is in BCNF and has no multi-valued dependencies (MVDs). Since B ↔ C indicates a multi-valued dependency, the table is not in 4NF.

Question 6: Partial Dependency Identification

Q6: A table with the following structure is given:

  • Attributes: {A, B, C, D}

  • Functional Dependencies: AB → C, A → D

Is there a partial dependency in this table?

  • A) Yes, because A → D

  • B) No, because AB → C

  • C) Yes, because AB is a composite key

  • D) No, because A is a candidate key

Answer: A) Yes, because A → D

Explanation: A partial dependency occurs when a non-key attribute depends on only a part of a composite primary key. Here, A → D means D depends only on A (not AB), which is a partial dependency.

Question 7: Transitive Dependency Identification

Q7: A table with the following structure is given:

  • Attributes: {A, B, C}

  • Functional Dependencies: A → B, B → C

Is there a transitive dependency in this table?

  • A) Yes, because A → B and B → C

  • B) No, because A → B

  • C) Yes, because A is the primary key

  • D) No, because there are no partial dependencies

Answer: A) Yes, because A → B and B → C

Explanation: A transitive dependency occurs when A → B and B → C implies A → C indirectly. This is a violation of 3NF.

Question 8: Candidate Key Identification

Q8: A table with the following structure is given:

  • Attributes: {A, B, C, D}

  • Functional Dependencies: AB → C, AB → D

Which of the following is a candidate key?

  • A) A

  • B) B

  • C) AB

  • D) CD

Answer: C) AB

Explanation: A candidate key is a minimal key that determines all attributes. Here, AB determines C and D, so AB is the candidate key.

Question 9: 2NF Violation Identification

Q9: A table with the following structure is given:

  • Attributes: {A, B, C}

  • Functional Dependencies: AB → C, A → B

Why is this table not in 2NF?

  • A) It is in 2NF

  • B) Because of partial dependency A → B

  • C) Because of transitive dependency AB → C

  • D) Because it is in 3NF

Answer: B) Because of partial dependency A → B

Explanation: Since A → B exists and AB is the primary key, this is a partial dependency (B depends on part of a composite key), violating 2NF.

Question 10: Normal Form Classification

Q10: A table with the following structure is given:

  • Attributes: {A, B, C, D}

  • Functional Dependencies: A → B, C → D, A → C, B → D

In which normal form is this table?

  • A) 1NF

  • B) 2NF

  • C) 3NF

  • D) BCNF

Answer: D) BCNF

Explanation: Since all determinants (A, C, B) are candidate keys, this table satisfies BCNF.


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