RDBMS Questions and Answers – Reduction to Relational Schema

This set of RDBMS Interview Questions and Answers for Experienced people focuses on “Reduction to Relational Schema”.

1. For schemas derived from strong entity sets, the _______ of the entity set serves as the primary key of the resulting schema
a) First attribute
b) Primary key
c) Foreign key
d) None of the mentioned
View Answer

Answer: b
Explanation: For schemas derived from strong entity sets, the primary key of the entity set serves as the primary key of the resulting schema. This is because the primary keys are to be preserved as they are unique.

2. State true or false: Derived attributes cannot be directly represented in the relational data model
a) True
b) False
View Answer

Answer: a
Explanation: Derived attributes cannot be directly represented in the relational data model. Instead, they are represented as methods.

3. The primary key of the representation of a weak entity set consists of the primary key of the strong entity set and the _______
a) Discriminator of the weak entity set
b) Foreign key
c) Primary key of all the other entity sets
d) All the attributes of the weak entity set
View Answer

Answer: a
Explanation: The primary key of the representation of a weak entity set consists of the primary key of the strong entity set and the discriminator of the weak entity set.
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4. For a binary many to many relationship, the ________ of the participating entity sets becomes the prime attribute
a) Intersection of primary keys
b) Primary key of either one
c) Union of primary keys
d) Primary key on the many side
View Answer

Answer: c
Explanation: For a binary many to many relationship, the union of the primary keys of the participating entity sets becomes the prime attribute.

5. For a binary one to one relationship, the ________ of the participating entity sets becomes the prime attribute
a) Intersection of primary keys
b) Primary key of either one
c) Union of primary keys
d) Primary key on the many side
View Answer

Answer: b
Explanation: For a binary one to one relationship, the primary key of either one of the participating entity sets becomes the prime attribute.
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6. For a binary many to many relationship, the ________ of the participating entity sets becomes the prime attribute
a) Intersection of primary keys
b) Primary key of either one
c) Union of primary keys
d) Primary key on the many side
View Answer

Answer: d
Explanation: For a binary many to many relationship, the primary key on the many side of the participating entity sets becomes the prime attribute.

7. For a n-ary relationship set without arrows, the ________ of the participating entity sets becomes the prime attribute
a) Intersection of primary keys
b) Primary key of either one
c) Union of primary keys
d) Primary key on the many side
View Answer

Answer: c
Explanation: For a binary many to many relationship, the union of the primary keys of the participating entity sets becomes the prime attribute.
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8. State true or false: The schema for the relationship set linking a weak entity set to its corresponding strong entity set is redundant.
a) True
b) False
View Answer

Answer: a
Explanation: The schema for the relationship set linking a weak entity set to its corresponding strong entity set is redundant and it need not be present in the relational database design derived from an ER diagram.

9. Statement 1: We can create foreign key constraints on relational schema derived from ER diagram
Statement 2: Relational schema cannot be derived from an ER diagram
a) Both the statements are true
b) Both the statements are false
c) Statement 1 is true and Statement 2 is false
d) Statement 2 is true and statement 1 is false
View Answer

Answer: c
Explanation: We can create foreign key constraints on relational schema derived from ER diagram and also it is possible to derive relational schema from ER diagrams.
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10. Which of the following can affect the placement of the relationship attributes?
a) Alphabetical order
b) The data in the attribute
c) Cardinality ratio
d) None of the mentioned
View Answer

Answer: c
Explanation: The cardinality ratio of a relationship can affect the placement of relationship attributes. The placement of the relationship attributes are not dependent on the alphabetical orderor the data in the attribute.

Sanfoundry Global Education & Learning Series – RDBMS.

To practice all areas of RDBMS for Interviews, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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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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