Database Questions and Answers – The Entity-Relationship Model

This set of Database Multiple Choice Questions & Answers (MCQs) focuses on “The Entity-Relationship Model”.

1. An ________ is a set of entities of the same type that share the same properties, or attributes.
a) Entity set
b) Attribute set
c) Relation set
d) Entity model
View Answer

Answer: a
Explanation: An entity is a “thing” or “object” in the real world that is distinguishable from all other objects.

2. Entity is a _________
a) Object of relation
b) Present working model
c) Thing in real world
d) Model of relation
View Answer

Answer: c
Explanation: For example, each person in a university is an entity.

3. The descriptive property possessed by each entity set is _________
a) Entity
b) Attribute
c) Relation
d) Model
View Answer

Answer: b
Explanation: Possible attributes of the instructor entity set are ID, name, dept name, and salary.

4. The function that an entity plays in a relationship is called that entity’s _____________
a) Participation
b) Position
c) Role
d) Instance
View Answer

Answer: c
Explanation: A relationship is an association among several entities.

5. The attribute name could be structured as an attribute consisting of first name, middle initial, and last name. This type of attribute is called
a) Simple attribute
b) Composite attribute
c) Multivalued attribute
d) Derived attribute
View Answer

Answer: b
Explanation: Composite attributes can be divided into subparts (that is, other attributes).

6. The attribute AGE is calculated from DATE_OF_BIRTH. The attribute AGE is
a) Single valued
b) Multi valued
c) Composite
d) Derived
View Answer

Answer: d
Explanation: The value for this type of attribute can be derived from the values of other related attributes or entities.

7. Not applicable condition can be represented in relation entry as
a) NA
b) 0
d) Blank Space
View Answer

Answer: c
Explanation: NULL always represents that the value is not present.

8. Which of the following can be a multivalued attribute?
a) Phone_number
b) Name
c) Date_of_birth
d) All of the mentioned
View Answer

Answer: a
Explanation: Name and Date_of_birth cannot hold more than 1 value.

9. Which of the following is a single valued attribute
a) Register_number
b) Address
d) Reference
View Answer

Answer: a
Explanation: None.

10. In a relation between the entities the type and condition of the relation should be specified. That is called as______attribute.
a) Desciptive
b) Derived
c) Recursive
d) Relative
View Answer

Answer: a
Explanation: Consider the entity sets student and section, which participate in a relationship set takes. We may wish to store a descriptive attribute grade with the relationship to record the grade that a student got in the class.

Sanfoundry Global Education & Learning Series – Database Management System.

The Entity-Relationship Model

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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