Database Normalization: Master Data Integrity and Efficiency

Question 1

What is the primary advantage of database normalization?

Accepted Answer

Reduced data redundancy

Answer

Improved data access performance

Answer

Increased data storage efficiency

Answer

Simplified data modification process

Question 2

What is a potential disadvantage of normalizing a database?

Accepted Answer

Increased data complexity

Answer

Reduced data redundancy

Answer

Improved data integrity

Answer

Increased data accessibility

Question 3

What is the primary purpose of a foreign key in a database?

Accepted Answer

To enforce referential integrity

Answer

To uniquely identify a row

Answer

To establish a relationship between two tables

Answer

To prevent data duplication

Question 4

In a relational database, what is the purpose of a composite key?

Accepted Answer

To uniquely identify a row using a combination of multiple columns

Answer

To enforce referential integrity between related tables

Answer

To enhance data retrieval performance by creating additional indexes

Answer

To ensure data integrity within a single table by preventing duplicate rows

Question 5

Which of the following is a common technique used in database normalization?

Accepted Answer

Attribute decomposition

Answer

Data type conversion

Answer

Index creation

Answer

Tuple insertion

Question 6

Which of the following scenarios describes a denormalized database?

Accepted Answer

A database where a particular data item is stored in multiple locations

Answer

A database with all tables in 3NF or higher

Answer

A database that does not use any foreign keys

Answer

A database that has very few tables

Question 7

What are the key advantages of database normalization?

Accepted Answer

Eliminates data redundancy

Accepted Answer

Ensures data consistency

Accepted Answer

Enhances query performance

Question 8

Which of the following is NOT an advantage of database normalization?

Accepted Answer

Complicates database design

Answer

Eliminates data redundancy

Answer

Enhances data integrity

Answer

Improves data flexibility

Question 9

Consider the relation:

Orders(orderID, customerID, productID, quantity)

Which of the following decompositions into smaller relations is in 2NF?

Accepted Answer

Orders1(orderID, customerID), Orders2(orderID, productID, quantity)

Answer

Orders1(orderID, productID), Orders2(orderID, customerID, quantity)

Answer

Orders1(orderID, customerID, productID), Orders2(quantity)

Answer

Orders1(orderID), Orders2(customerID), Orders3(productID), Orders4(quantity)

Question 10

Which of the following is a Boyce-Codd Normal Form (BCNF) violation?

Accepted Answer

A non-prime attribute is dependent on a proper subset of a candidate key

Answer

A non-prime attribute is dependent on a candidate key

Answer

A prime attribute is dependent on a non-prime attribute

Answer

A candidate key has a trivial functional dependency

Question 11

Which of the following is a lossless-join decomposition?

Accepted Answer

A decomposition that preserves all functional dependencies in the original relation

Answer

A decomposition that eliminates all functional dependencies in the original relation

Answer

A decomposition that creates new functional dependencies in the smaller relations

Answer

A decomposition that removes all candidate keys from the smaller relations

Question 12

Which of the following is a violation of the second normal form (2NF)?

Accepted Answer

A table with non-key attributes dependent on only part of the primary key.

Answer

A table with a primary key.

Answer

A table with unique values in all columns.

Answer

A table with no transitive dependencies.

Question 13

Which of the following is a technique for achieving database normalization?

Accepted Answer

Decomposition

Answer

Aggregation

Answer

Normalization

Answer

Clustering

Question 14

In First Normal Form (1NF), each record in a table must have:

Accepted Answer

No repeating groups (atomic values)

Answer

A unique primary key

Answer

All attributes with atomic values

Answer

No null values

Question 15

Which of the following is a key dependency violation in 2NF?

Accepted Answer

A non-key attribute is functionally dependent on only a proper subset of the primary key

Answer

The primary key is not unique

Answer

A non-key attribute is functionally dependent on another non-key attribute

Answer

There are duplicate rows in the table

Question 16

Identify a potential benefit of denormalization:

Accepted Answer

Improved query performance

Answer

Reduced storage space

Answer

Increased data accuracy

Answer

Elimination of data redundancy

Question 17

The normalization process is primarily applied to which type of data model?

Accepted Answer

Relational databases

Answer

Hierarchical databases

Answer

Network databases

Answer

Object-oriented databases

Question 18

According to 1NF, which of the following must ALL attributes of a table be?

Accepted Answer

Atomic and indivisible

Answer

Dependent on the primary key

Answer

Unique for each row

Question 19

A table is said to be in 2NF if it satisfies which additional condition beyond 1NF?

Accepted Answer

Every non-key attribute is fully dependent on the primary key.

Answer

There are no multivalued dependencies.

Answer

All primary key attributes are atomic and indivisible.

Question 20

Which of the following is NOT among the benefits of normalization?

Accepted Answer

Increased data inconsistency

Answer

Reduced data redundancy

Answer

Improved query performance

Question 21

Consider the following table:

Employees (EmployeeID, EmployeeName, DepartmentID, DepartmentName)

Which of the following represents a denormalized form of this table?

Accepted Answer

Employees (EmployeeID, EmployeeName, DepartmentName)

Answer

Employees (EmployeeID, EmployeeName, DepartmentID)

Question 22

Among the normal forms (1NF, 2NF, 3NF, and BCNF), which one represents the highest level of normalization?

Accepted Answer

BCNF

Answer

1NF

Answer

2NF

Answer

3NF

Question 23

Which of the following decomposition techniques is designed to eliminate transitive dependencies?

Accepted Answer

Lossless-join decomposition

Answer

Horizontal decomposition

Answer

Vertical decomposition

Question 24

Consider the following table:

Students (StudentID, StudentName, CourseID, CourseName)

Which of the following represents a multivalued dependency?

Accepted Answer

StudentID -> CourseID

Answer

CourseID -> CourseName

Answer

StudentID -> StudentName

Question 25

Which of the following is a potential drawback of database normalization?

Accepted Answer

Increased query complexity

Answer

Reduced data redundancy

Answer

Improved data integrity

Question 26

Consider the following table:

Customers (CustomerID, CustomerName, Address, PhoneNumber, Email)

Which of the following is a candidate key for this table?

Accepted Answer

CustomerID

Answer

CustomerName

Answer

PhoneNumber

Question 27

In which normal form are all non-key attributes directly dependent on the primary key, and no non-key attribute is dependent on any other non-key attribute?

Accepted Answer

2NF

Answer

1NF

Answer

3NF

Answer

BCNF

Question 28

The process of dividing a table into smaller tables to eliminate data anomalies and improve data integrity is known as:

Accepted Answer

Normalization

Answer

Denormalization

Answer

Decomposition

Answer

Refactoring

Question 29

One potential drawback of over-normalizing a database is:

Accepted Answer

Reduced query performance

Answer

Increased data redundancy

Answer

Increased data inconsistency

Answer

Simplified database design

Question 30

The key difference between 2NF and 3NF is that:

Accepted Answer

2NF eliminates partial functional dependencies, while 3NF eliminates transitive functional dependencies

Answer

2NF eliminates transitive functional dependencies, while 3NF eliminates partial functional dependencies

Answer

Both 2NF and 3NF eliminate transitive functional dependencies

Answer

Neither 2NF nor 3NF eliminates transitive functional dependencies

Question 31

Which of the following is a graphical representation of the relationships between tables in a database?

Accepted Answer

Entity-Relationship Diagram

Answer

Data Flow Diagram

Answer

Use Case Diagram

Answer

Class Diagram

Question 32

Which of the following is considered to be the weakest normal form?

Accepted Answer

1NF

Answer

2NF

Answer

3NF

Answer

BCNF

Question 33

Which condition is NOT necessary for a relation to be in 2NF?

Accepted Answer

All non-key attributes must rely solely on the primary key.

Answer

It must satisfy 1NF.

Answer

All non-key attributes must depend on at least one candidate key.

Answer

It must not contain transitive dependencies.

Question 34

Which normal form is considered the most stringent?

Accepted Answer

BCNF

Answer

1NF

Answer

2NF

Answer

3NF

Question 35

Which technique involves intentionally duplicating data?

Accepted Answer

Data replication

Answer

Redundant column addition

Answer

Summary table creation

Answer

Data integrity constraint enforcement

Question 36

Under what circumstances is denormalization appropriate?

Accepted Answer

When query speed is critical

Answer

When data integrity is of no concern

Answer

When the database is small

Answer

Never

Question 37

What is the recommended sequence for applying normalization forms?

Accepted Answer

1NF, 2NF, 3NF, BCNF

Answer

BCNF, 3NF, 2NF, 1NF

Answer

2NF, 3NF, 1NF, BCNF

Answer

3NF, 1NF, 2NF, BCNF

Question 38

In 2NF, a table is said to be in 1NF and additionally, each non-key attribute must be...?

Accepted Answer

Functionally dependent on the primary key.

Answer

Functionally dependent on every other non-key attribute.

Answer

Independent of all other attributes in the table.

Question 39

Boyce-Codd Normal Form (BCNF) is a stricter normalization form than 3NF. Which of the following conditions must be met in BCNF?

Accepted Answer

Every determinant in the table must be a candidate key.

Answer

All primary keys must be foreign keys.

Answer

There must be no transitive dependencies in the table.

Question 40

Which of the following techniques is commonly employed to normalize a relational database?

Accepted Answer

Decomposition

Answer

Aggregation

Answer

Merging

Answer

Denormalization

Question 41

Normalization of a database can sometimes lead to certain drawbacks. Which of the following is a potential disadvantage of normalization?

Accepted Answer

Increased query complexity

Answer

Reduced storage space

Answer

Improved data consistency

Answer

Enhanced data accuracy

Question 42

The primary objective of database normalization is to...

Accepted Answer

Improve the logical structure of a database by reducing data redundancy and anomalies.

Answer

Reduce data integrity.

Answer

Make a database more difficult to query.

Answer

Increase data redundancy.

Question 43

Which of the following is the primary objective of database normalization?

Accepted Answer

Eliminating duplicate data and ensuring data consistency

Answer

Enhancing data integrity

Answer

Reducing storage space

Answer

Improving query performance

Question 44

Which of the following is a violation of 2NF?

Accepted Answer

Non-key attributes are dependent on a proper subset of the primary key

Answer

Presence of transitive dependencies

Answer

Attributes are not atomic

Answer

Existence of repeating groups

Question 45

What is the significance of achieving 3NF?

Accepted Answer

Eliminates transitive dependencies within a relation

Answer

Simplifies data retrieval

Answer

Guarantees referential integrity

Answer

Prevents data duplication

Question 46

Which normal form requires that all functional dependencies are key dependencies?

Accepted Answer

Boyce-Codd Normal Form (BCNF)

Answer

Third Normal Form (3NF)

Answer

Second Normal Form (2NF)

Answer

First Normal Form (1NF)

Question 47

What is a potential disadvantage of applying higher normal forms?

Accepted Answer

Increased number of relations and joins, potentially affecting query performance

Answer

Reduced data integrity

Answer

Increased storage space requirements

Answer

Difficulty in data maintenance

Question 48

What is the primary benefit of data normalization?

Accepted Answer

Improved data integrity and reduced data redundancy

Answer

Enhanced data security

Answer

Simplified data maintenance

Answer

Faster query execution

Question 49

Which of the following is NOT a characteristic of first normal form (1NF)?

Accepted Answer

Primary keys can contain duplicate values.

Answer

Each row is uniquely identified by a primary key.

Answer

No repeating groups within rows.

Answer

All attributes are atomic (indivisible).

Question 50

A relation is in second normal form (2NF) if it meets which of these conditions?

Accepted Answer

It is in 1NF and every non-key attribute is fully dependent on the primary key.

Answer

There are no repeating groups within rows.

Answer

Every attribute is atomic.

Question 51

What is a primary benefit of normalizing a database?

Accepted Answer

Improved data integrity and efficiency.

Answer

Reduced storage requirements.

Answer

Increased data redundancy.

Question 52

Which normalization form ensures that every functional dependency is either a trivial dependency or directly dependent on the primary key?

Accepted Answer

Boyce-Codd normal form (BCNF).

Answer

Second normal form (2NF).

Answer

First normal form (1NF).

Answer

Third normal form (3NF).

Question 53

Which statement accurately describes denormalization?

Accepted Answer

It can improve query performance by introducing controlled redundancy, potentially sacrificing some data integrity.

Answer

It is always the preferred approach to database design.

Answer

It involves converting normalized data into unnormalized data.

Question 54

What is a potential drawback of using Boyce-Codd normal form (BCNF)?

Accepted Answer

It can lead to more complex queries due to increased table joins.

Answer

It is easier to implement than other normalization forms.

Answer

It ensures higher data integrity.

Answer

It reduces data redundancy.

Question 55

When should fourth normal form (4NF) be considered?

Accepted Answer

When multi-valued dependencies exist, meaning an attribute can have multiple values for a single instance.

Answer

When transitive dependencies exist.

Answer

When join dependencies exist.

Answer

When inclusion dependencies exist.