ER and Relational Models

Question 31

Consider a relation R (A, B, C, D, E, F, G, H), where each attribute is atomic, and following functional dependencies exist.

CH → G
A → BC
B → CFH
E → A
F → EG

The relation R is __________ .

• in 1NF but not in 2NF
• in 2NF but not in 3NF
• in 3NF but not in BCNF
• in BCNF

Question 32

Which symbol denote derived attributes in ER Model?

• Double ellipse
• Dashed ellipse
• Squared ellipse
• Ellipse with attribute name underlined

Question 33

Integrity constraints ensure that changes made to the database by authorized users do not result into loss of data consistency. Which of the following statement(s) is (are) true w.r.t. the examples of integrity constraints ? 
(A) An instructor Id. No. cannot be null, provided Instructor Id No. being primary key. 
(B) No two citizens have same Aadhaar-Id. 
(C) Budget of a company must be zero.

• (A), (B) and (C) are true.

• (A) false, (B) and (C) are true.

• (A) and (B) are true; (C) false.

• (A), (B) and (C) are false

Question 34

Let M and N be two entities in an E-R diagram with simple single value attributes. R₁ and R₂ are two relationship between M and N, where as R₁ is one-to-many and R₂ is many-to-many. The minimum number of tables required to represent M, N, R₁ and R₂ in the relational model are _______.

• 4
• 6
• 7
• 3

Question 35

Which one is correct w.r.t. RDBMS ?

• primary key ⊆ super key ⊆ candidate key
• primary key ⊆ candidate key ⊆ super key
• super key ⊆ candidate key ⊆ primary key
• super key ⊆ primary key ⊆ candidate key

Question 36

Let pk(R) denotes primary key of relation R. A many-to-one relationship that exists between two relations R₁ and R₂ can be expressed as follows :

• pk(R₂) → pk(R₁)
• pk(R₁) → pk(R₂)
• pk(R₂) → R₁ ∩ R₂
• pk(R₁) → R₁ ∩ R₂

Question 37

Consider the join of a relation R , with a relation S . If R has m number of tuples and S has n number of tuples then the maximum and minimum sizes of the join respectively are:

• m + n & 0

• mn & 0

• m + n & | m - n |

• mn & m + n

Question 38

Let R(a, b, c) and S(d, e, f) be two relations in which d is the foreign key of S that refers to the primary key of R. Consider the following four operations R and S. I. Insert into R II. Insert into S III. Delete from R IV. Delete from S Which of the following can cause violation of the referential integrity constraint above?

• Both I and IV
• Both II and III
• All of these
• None of these

Question 39

Goals for the design of the logical scheme include

• avoiding data inconsistency
• being able to construct query easily
• being able to access data efficiently
• All of the above

Question 40

Consider the following Relationship Entity Diagram(ERD) Which of the following possible relations will not hold if the above ERD is mapped into a relation model?

• Person (NID, Name)
• Qualification (NID, ExamID, QualifiedDate)
• Exam (ExamID, NID, ExamName)
• Exam (ExamID, ExamName)