Databases - Review Questions With Answers

What is the difference between VARCHAR and INT data types?

• VARCHAR stores variable-length text

• INT is used for whole numbers

Answer explanation

VARCHAR is designed to store variable-length text, making it suitable for strings of different sizes. INT, on the other hand, is specifically for whole numbers, allowing for efficient storage and calculations with numeric data.

Which data type would you use for storing dates in a database?

• DATE

• STRING

• INTEGER

• FLOAT

Answer explanation

The DATE data type is specifically designed to store date values in a database, allowing for proper date manipulation and querying. Other types like STRING, INTEGER, and FLOAT are not suitable for date storage.

What data type should you choose for a column that stores boolean values (e.g., TRUE/FALSE)?

• BOOLEAN

• INTEGER

• VARCHAR

• FLOAT

Answer explanation

The BOOLEAN data type is specifically designed to store true/false values, making it the ideal choice for a column that needs to represent boolean values. Other types like INTEGER or VARCHAR are not suitable for this purpose.

Activity Question: Given a "Student" table with columns StudentID, Name, EnrollmentDate, and IsActive, choose appropriate data types. Answer: StudentID: INT, Name: VARCHAR, EnrollmentDate: DATE, IsActive: BOOLEAN

• StudentID: INT, Name: VARCHAR, EnrollmentDate: DATE, IsActive: BOOLEAN

• StudentID: STRING, Name: TEXT, EnrollmentDate: DATETIME, IsActive: INT

• StudentID: NUMBER, Name: CHAR, EnrollmentDate: TIMESTAMP, IsActive: STRING

• StudentID: INTEGER, Name: STRING, EnrollmentDate: TEXT, IsActive: BOOL

Answer explanation

The correct choice specifies appropriate data types: INT for StudentID (numeric), VARCHAR for Name (variable-length string), DATE for EnrollmentDate (date type), and BOOLEAN for IsActive (true/false).

In a database, Yes/No, Text and Date/Time are all examples of:

• data types

• data queries

• tabs you can select

• records in the data table

Answer explanation

Yes/No, Text, and Date/Time are all examples of data types, which define the kind of data that can be stored in a database. Therefore, the correct answer is 'data types'.

A data type that can only hold 2 values e.g. Yes/No or True/False.

• Boolean

• Integer

• Real

• String

Answer explanation

The correct answer is 'Boolean' because it is a data type that can only hold two values, such as Yes/No or True/False. Other options like Integer, Real, and String can hold multiple values, making them incorrect.

A data type used for storing numbers with a fractional part e.g. 3.142

• Integer

• Boolean

• Real / Float

• String

Answer explanation

The correct answer is 'Real / Float' because it represents data types that can store numbers with fractional parts, such as 3.142. In contrast, 'Integer' stores whole numbers, 'Boolean' stores true/false values, and 'String' stores text.