SQL Entity Relationship Model MCQ
Entity Relationship Model MCQs : This section focuses on the "Entity Relationship Model" of the SQL. These Multiple Choice Questions (MCQs) should be practiced to improve the SQL skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
1. A many to many relationship between two entities usually results in how many tables?
A. One
B. Two
C. Three
D. Four
View Answer
Ans : C
Explanation: A many to many relationship between two entities usually results in Three tables.
2. 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
Ans : A
Explanation: An entity is a "thing" or "object" in the real world that is distinguishable from all other objects.
3. Entity is a _________
A. Object of relation
B. Present working model
C. Thing in real world
D. Model of relation
View Answer
Ans : C
Explanation: For example, each person in a university is an entity.
4. In a many to one relationship, the primary key of one entity acts as foreign key on which side?
A. On the side where single (one) relationship is defined
B. On the side where many relationship is defined
C. On both the sides
D. Neither of them
View Answer
Ans : B
Explanation: In a many to one relationship, the primary key of one entity acts as foreign key of On the side where many relationship is defined
5. Every weak entity set can be converted into a strong entity set by:
A. using generalization
B. adding appropriate attributes
C. using aggregation
D. none of the above
View Answer
Ans : B
Explanation: Every weak entity set can be converted into a strong entity set by adding appropriate attributes.
6. A weak entity set in an E-R diagram is an entity set that :
A. has a primary key
B. must be part of a one to many relationship set
C. is not existence dependent on a dominant entity
D. must not participate as owner in an identifying relationship with another entity set
View Answer
Ans : B
Explanation: A weak entity set in an E-R diagram is an entity set that must be part of a one to many relationship set.
7. In an E-R, Y is the dominant entity and X is a subordinate entity. Then which of the following is incorrect ?
A. operationally, If Y is deleted, so is X
B. operationally, if X is deleted, Y remains the same
C. operationally, if X is deleted, so is Y
D. X existence is dependent on Y
View Answer
Ans : D
Explanation: X existence is dependent on Y is incorrect.
8. Choose the most appropriate choice with respect to conceptual design.
A. Conceptual design is a documentation technique. Once the relation schemes are defined one can draw E-R diagrams from the relation schemes for documentation
B. Conceptual design needs data volumn and processing frequencies to determine the size of the database
C. Output of any conceptual design is an E-R diagram
D. Conceptual design involves modeling the data requirements independent of the DBMS, operating system and the hardware.
View Answer
Ans : D
Explanation: Conceptual design involves modeling the data requirements independent of the DBMS, operating system and the hardware is the most appropriate choice with respect to conceptual design.
9. E-R modeling technique is a :
A. Top-down approach
B. Bottom-up approach
C. Left-right approach
D. None of the above
View Answer
Ans : A
Explanation: E-R modeling technique is a Top-down approach.
10. The number of entities to which another entity can be associated via a relationship set is expressed as :
A. Entity
B. Cardinality
C. Schema
D. Attributes
View Answer
Ans : B
Explanation: The number of entities to which another entity can be associated via a relationship set is expressed as Cardinality.
11. Every weak entity set can be converted to a strong entity set by :
A. Using generalization
B. Simply adding appropriate attribute
C. Using aggregation
D. Repeating the entity set several times
View Answer
Ans : A
Explanation: Every weak entity set can be converted to a strong entity set by Using generalization
12. Relations produced from an E-R model will always be in :
A. First normal form
B. Second normal form
C. Third normal form
D. Fourth normal form
View Answer
Ans : C
Explanation: Relations produced from an E-R model will always be in Third normal form
13. In ER model the details of the entities are hidden from the user. This process is called :
A. generalization
B. specialization
C. abstraction
D. none of these above
View Answer
Ans : C
Explanation: In ER model the details of the entities are hidden from the user. This process is called abstraction.
14. The attributes made up of more than one single attributes are called
A. Composite attribute
B. Derived attribute
C. Single value attribute
D. Multi value attribute
View Answer
Ans : A
Explanation: The attributes made up of more than one single attributes are called Composite attribute
15. 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
Ans : D
Explanation: The value for this type of attribute can be derived from the values of other related attributes or entities.
16. 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
Ans : A
Explanation: Name and Date_of_birth cannot hold more than 1 value.
17. Which of the following is a single valued attribute?
A. Register_number
B. Address
C. SUBJECT_TAKEN
D. Reference
View Answer
Ans : A
Explanation: Register_number is a single valued attribute.
18. An association of several entities in an Entity-Relation model is called :
A. Tuple
B. Record
C. Relationship
D. Field
View Answer
Ans : C
Explanation: An association of several entities in an Entity-Relation model is called Relationship.
19. Which of the following statements are true?
I. Entity Relationship Model is process oriented Model
II. Entity Relationship model belong to Semantic model category
A. I Only True
B. II Only True
C. Both I And II
D. None of the above
View Answer
Ans : A
Explanation: Entity Relationship Model is process oriented Model is true.
20. We wish to ensure that a value that appears in one relation for a given set of attributes also appears for a certain set of attributes in another relation. This condition is called ___________ .
A. Join integrity
B. Relational integrity
C. Referential integrity
D. Set integrity
View Answer
Ans : B
Explanation: We wish to ensure that a value that appears in one relation for a given set of attributes also appears for a certain set of attributes in another relation. This condition is called Relational integrity.
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