Tuesday, September 1, 2020

Entity Relationship (ER) model quiz

ER model multiple choice questions with answers explained, simple quiz questions from ER model in database management system

Entity Relationship Model Multiple Choice Questions

1. Which of the following questions cannot be answered using the given ER model?  

entity relationship diagram

(a) What is the total number of particular product purchased by a customer?

(b) What is the price of the product which was purchased by a particular customer in a particular date?

(c) What is the total number of particular product that is ordered through a specific order number?

(d) What is the address of customer who placed more number of orders to date?


Answer: Option (d)


2. Statement A: The cardinality of a relation is the number of tuples it contains.

Statement B: The degree of a relation is the number of records it contains.

Which statement(s) is/are correct?

a) Only B

b) A and B

c) Only A

d) Neither A nor B


Answer: Option (c)


3. The file organization technique used in a table is hidden from the application programmers in the database environment. What kind of data hiding is this?

a) Conceptual level data hiding

b) Physical level data hiding

c) View level data hiding

d) External level data hiding


Answer: Option (b)

File organization is about how the data are organized in the database file. It is one of the physical level components in database.


4. “SELECT regno, name, dob FROM students WHERE gender = ‘M’”. This is NOT a type of which among the following languages.

a) Data Definition Language

b) Procedural Data Manipulation Language

c) Declarative Data Manipulation Language

d) Non-procedural Data Manipulation Language


Answer: Options (a) and (b)

The query given is a Data Manipulation Language (DML) query. And, SQL DMLs are non-procedural DML also called as Declarative DML.


5. Suppose that there are two entity sets A and B with attributes a1, a2, a3 and b1, b2, b3 respectively. Here, a1 is the key for A and b2 is the key for B. If there exists a many-to-many relationship R from A to B with an attribute r1, what would be the schema for R after converting the ER diagram into schemas?

a. R(a1, a1)

b. R(a1, b2)

c. R(a1, b1, b2)

d. R(a1, b2, r1)


Answer: Option (d)

While reducing many-to-many relationship into relation schema, we create a separate table with the primary keys of participating entity sets as the attributes along with descriptive attributes if any. In this question, r1 is the descriptive attribute.



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