Data Types and Constraints: Master Data Integrity in Database Management

Question 1

What data type is appropriate for storing a student's name?

Accepted Answer

Character

Answer

Integer

Answer

Date

Question 2

What is the primary objective of a primary key constraint?

Accepted Answer

To guarantee that each table row possesses a distinct identifier.

Answer

To prevent the entry of duplicate values into a column.

Answer

To impose a specific data type on a column.

Answer

To restrict the number of rows in a table.

Question 3

Identify the defining characteristic of the VARCHAR data type:

Accepted Answer

Stores a variable number of characters.

Answer

Stores a fixed number of characters.

Answer

Can only store numeric values.

Answer

Designed for storing temporal data.

Question 4

Explain the distinction between a NOT NULL constraint and a UNIQUE constraint:

Accepted Answer

NOT NULL ensures a value is always provided while UNIQUE does not.

Answer

NOT NULL allows duplicate values while UNIQUE prevents them.

Answer

UNIQUE allows duplicate values while NOT NULL prevents them.

Answer

There is no significant difference between the two constraints.

Question 5

Which data type is appropriate for storing extensive text content?

Accepted Answer

Text

Answer

Character (Char)

Answer

Character Varying (Varchar)

Answer

Integer (Int)

Question 6

Explain the difference between a clustered index and a non-clustered index:

Accepted Answer

A clustered index physically organizes the table data, while a non-clustered index does not.

Answer

A non-clustered index physically organizes the table data, while a clustered index does not.

Answer

A clustered index is always unique, unlike a non-clustered index.

Answer

Clustered and non-clustered indexes are essentially the same.

Question 7

Which of the following is NOT an advantage of using constraints in a database?

Accepted Answer

Increased data complexity.

Answer

Improved data integrity and accuracy.

Answer

Reduced data duplication.

Answer

Enhanced database performance.

Question 8

What is the purpose of a DEFAULT constraint?

Accepted Answer

To provide a default value for a column when no value is explicitly specified.

Answer

To prevent the entry of duplicate values into a column.

Answer

To enforce a specific data type on a column.

Answer

To limit the number of rows in a table.

Question 9

Which constraint is used to make sure that a column cannot contain empty values?

Accepted Answer

NOT NULL

Answer

UNIQUE

Answer

PRIMARY KEY

Answer

FOREIGN KEY

Question 10

Which of the following is NOT a property of a primary key in a relational database?

Accepted Answer

It can be modified over time.

Answer

It uniquely identifies each row in a table.

Answer

It cannot contain duplicate values.

Answer

It can consist of multiple columns.

Question 11

Which constraint is used to define a condition that must be met by the data in a column?

Accepted Answer

CHECK

Answer

UNIQUE

Answer

NOT NULL

Answer

DEFAULT

Question 12

Which data type is designed for storing large binary objects, such as images or documents?

Accepted Answer

BLOB

Answer

RAW

Answer

BINARY

Answer

IMAGE

Question 13

Which data type is designed specifically for storing date and time information in a database?

Accepted Answer

Date/Time

Answer

Numeric

Answer

Character

Answer

Boolean

Question 14

Select the most appropriate data type and constraint for a database field that will store the age of customers.

Accepted Answer

Data type: Integer, Constraint: NOT NULL

Answer

Data type: Varchar(50), Constraint: UNIQUE

Answer

Data type: Date, Constraint: DEFAULT '1970-01-01'

Answer

Data type: Boolean, Constraint: CHECK (age > 0)

Question 15

What is the primary advantage of using constraints in a database?

Accepted Answer

Enforce data integrity and prevent inconsistencies

Answer

Reduce data redundancy

Answer

Improve database performance

Answer

Enhance database security

Question 16

Which data type in SQL is used to store whole numbers without decimal places?

Accepted Answer

Integer

Answer

Float

Answer

Double

Answer

Decimal

Question 17

Which data constraint specifies that a field cannot be left empty?

Accepted Answer

NOT NULL

Answer

UNIQUE

Answer

PRIMARY KEY

Answer

FOREIGN KEY

Question 18

What is the purpose of a referential integrity constraint?

Accepted Answer

To ensure that related data in different tables remains consistent.

Answer

To prevent duplicate data from being inserted.

Answer

To enforce a specific data type for a field.

Answer

To limit the number of records in a table.

Question 19

Which of the following data types is used to store binary data, such as images or videos?

Accepted Answer

BLOB

Answer

CLOB

Answer

TEXT

Answer

VARCHAR

Question 20

Which data type is used to store whole numbers, without decimal places?

Accepted Answer

INTEGER

Answer

FLOAT

Answer

REAL

Answer

DECIMAL

Question 21

Which type of constraint prevents a field from containing duplicate values?

Accepted Answer

UNIQUE

Answer

CHECK

Answer

PRIMARY KEY

Answer

FOREIGN KEY

Question 22

What is the purpose of a CHECK constraint in a database?

Accepted Answer

To restrict the values that can be entered into a field based on specified conditions.

Answer

To prevent null values in a field.

Answer

To enforce uniqueness of values in a field.

Question 23

What is the key difference between a PRIMARY KEY and a FOREIGN KEY?

Accepted Answer

A PRIMARY KEY uniquely identifies each record in a table, while a FOREIGN KEY establishes a relationship between two tables.

Answer

A PRIMARY KEY is always defined on a numeric field, while a FOREIGN KEY can be defined on any field.

Question 24

Which data type is suitable for storing large amounts of binary data, such as images or audio?

Accepted Answer

BLOB

Answer

SOUND

Answer

IMAGE

Answer

VIDEO

Question 25

What is the purpose of a NOT NULL constraint?

Accepted Answer

To prevent a field from containing a null value.

Answer

To restrict the values that can be entered into a field.

Answer

To enforce uniqueness of values in a field.

Question 26

What is the difference between a CHAR and a VARCHAR data type?

Accepted Answer

CHAR reserves a fixed amount of space for each value, regardless of its actual length, while VARCHAR allocates space only for the characters stored.

Answer

CHAR is used for numeric data, while VARCHAR is used for string data.