20 Database Management

1 Which one of these is the most appropriate data type to store data about student grades? (1)

A Numeric

B Alphanumeric/text

C Logical/Boolean

D Currency

B Alphanumeric/text

2 State the reason why a primary key is used in a database. (1)

A primary key is used in a database to uniquely identify each record or row in a table.

3 State two reasons why validation is used in a database. (2)

a) By implementing validation rules and checks, the database system can prevent incorrect or inconsistent data from being entered, thereby minimizing data entry errors.

b) Validation helps enforce referential integrity by ensuring that relationships between tables are maintained and that foreign key values are valid and consistent.

4 List three attributes that could be stored about a book entity in a library database. (3)

a) Title: This attribute stores the title or name of the book, which uniquely identifies it among other books in the library.

b) Author: This attributes stores the name of the author or authors who wrote the book. It helps identify the individual or individuals responsible for creating the book.

c) ISBN: International Standard Book Number (ISBN) is a unique identifier assigned to each published book. This attributes stores the ISBN of the book, which can be used for easy identification and referencing purposes.

5 Identify three validation checks that can be carried out on data. (3)

a) Data type validation which verifies that the entered data matches the expected data type.

b) Range validation which ensures that data falls within acceptable limits.

c) Format validation which validates data against predetermined patterns.

6 Explain why referential integrity is used in databases. (4)

Referential integrity is a crucial concept in database used to maintain the consistency and accuracy of relationships between tables. It ensures that the integrity of the data is preserved by enforcing rules and constraints on the relationships. By defining foreign key constraints, referential integrity guarantees that any value in a foreign key column must correspond to an existing value in the referenced primary key column. This prevents the creation of orphaned records or inconsistencies that could compromise the reliability and validity of the data. By upholding referential integrity, databases can maintain the integrity of relationships, support accurate data analysis, and provide a solid foundation for data-driven operations and decision-making.

7 State the type of validation check that would be used to select all records between specified dates. (1)

The type of validation check that would be used to select all records between specified dates is Range Validation.

8 Give the outcome of sorting this data in ascending order: 1, 6, 4, 3, 7. (1)

1, 3, 4, 6, 7

9 Give the result of evaluating this relational expression: 14>16. (1)

FALSE

10 A database contains data about boys and girls. Which one of these logical operations would return results about only girls? (1)

A Boy AND Girl

B Boy OR Girl

C NOT Boy

D NOT Girls

C NOT Boy