h

Question 1

What is the purpose of normalization?

Answer 1

To reduce data duplication and enhance data integrity

Normalization aims to organize a database to minimize redundancy and ensure data integrity.

Question 2

What is a transitive dependency?

Answer 2

A dependency of a non-key attribute on another non-key attribute

Transitive dependencies occur when one non-key attribute depends on another non-key attribute through a primary key.

Question 3

What is Boyce-Codd Normal Form (BCNF)?

Answer 3

A stricter version of 3NF

BCNF addresses certain types of anomalies not handled by 3NF.

Question 4

Which of the following is NOT a characteristic of functional dependencies?

Answer 4

Redundancy

Functional dependencies are defined by properties like reflexivity, transitivity, and union, but not redundancy.

Question 5

What is the main goal of the third normal form (3NF)?

Answer 5

To prevent transitive dependencies

3NF ensures that every non-key attribute is fully functionally dependent on the primary key.

Question 6

Which of the following is a candidate key?

Answer 6

A key that can uniquely identify a record

Candidate keys are potential primary keys that can uniquely identify records in a table.

Question 7

Which normal form requires that all functional dependencies be fully functional?

Answer 7

2NF

2NF eliminates partial dependencies of non-key attributes on the primary key.

Question 8

What is a primary key?

Answer 8

A unique identifier for a table

A primary key ensures that each record in a table can be uniquely identified.

Question 9

Which of the following is a violation of 2NF?

Answer 9

A composite primary key with non-key attributes

2NF requires that all non-key attributes are fully functionally dependent on the entire primary key.

Question 10

What is the outcome of normalization?

Answer 10

Enhanced data integrity

Normalization leads to a more reliable database structure with reduced data anomalies.

Question 11

Which of the following describes a surrogate key?

Answer 11

A system-generated unique identifier

Surrogate keys are often used in databases when natural keys are not available or suitable.

Question 12

What is denormalization?

Answer 12

The introduction of redundancy for performance purposes

Denormalization is used to improve database performance, especially in read-heavy environments.

Question 13

Which of the following statements is true about functional dependencies?

Answer 13

They can exist without primary keys.

Functional dependencies can be established even when a primary key is not defined.

Question 14

Which normal form eliminates transitive dependencies?

Answer 14

3NF

3NF ensures that non-key attributes do not depend on other non-key attributes.

Question 15

What is the main purpose of using composite keys?

Answer 15

To uniquely identify records when a single attribute is insufficient

Composite keys combine multiple attributes to form a unique identifier.

Question 16

What is a functional dependency closure?

Answer 16

The set of all attributes that can be functionally determined by a set of attributes

This closure helps in understanding the implications of functional dependencies in a database.

Question 17

Which normalization form does not allow any multi-valued dependencies?

Answer 17

4NF

4NF addresses multi-valued dependencies to ensure data is organized correctly.

Question 18

What signifies a relation being in 1NF?

Answer 18

All attributes are atomic

1NF requires that each attribute contains only indivisible values.

Question 19

What is a foreign key?

Answer 19

A key that links two tables together

Foreign keys establish relationships between tables by referencing primary keys in other tables.

Question 20

Which of the following is an advantage of normalization?

Answer 20

Reduced redundancy

Normalization minimizes duplicate data and helps maintain data integrity.

Question 21

What is the main goal of functional dependency analysis?

Answer 21

To identify relationships among attributes

Understanding functional dependencies aids in database design and normalization.

Question 22

In which normal form can a relation have no non-prime attributes?

Answer 22

BCNF

BCNF requires that every determinant in a functional dependency is a candidate key.

Question 23

In relation to database design, what does ‘lossless decomposition’ refer to?

Answer 23

Breaking down a table without losing data

Lossless decomposition maintains the original data when dividing tables.

Question 24

Which normal form is achieved by eliminating multi-valued dependencies?

Answer 24

4NF

4NF addresses scenarios where an attribute can have multiple values independently of other attributes.

Question 25

What does it mean for a database to be in BCNF?

Answer 25

Every determinant is a candidate key ## Footnote BCNF is stricter than 3NF and ensures no anomalies due to functional dependencies.

Question 26

Which of the following is an example of a transitive dependency?

Answer 26

A → B and B → C implies A → C ## Footnote Transitive dependencies can lead to redundancy and anomalies in databases.

Question 27

Which of the following is a disadvantage of denormalization?

Answer 27

Reduced data integrity ## Footnote Denormalization can introduce anomalies and inconsistencies in the data.

Question 28

What does it mean for a database to be in 2NF?

Answer 28

No partial dependencies ## Footnote 2NF ensures that all non-key attributes depend on the whole primary key, not just part of it.

Question 29

Which normal form does not allow any transitive dependencies?

Answer 29

3NF ## Footnote 3NF specifically addresses the elimination of transitive dependencies among attributes.

Question 30

Why is denormalization sometimes used in database design?

Answer 30

To enhance performance for read-heavy applications ## Footnote Denormalization can speed up query performance by reducing the number of joins needed.