Topic 5 Part 2

Question 1

Define a table:

Answer 1

A collection of records organised into rows and columns within a database.

Question 2

Where can we find databases?

Answer 2

Websites (e.g., login systems)
Banking systems
Retail and inventory systems

Question 3

What does an entity represent in a database?:

Answer 3

An object or concept with attributes, like a customer or product.

Question 4

What is another term for field?:

Answer 4

Attribute

Question 5

Define the term foreign key:

Answer 5

A field in one table that links to the primary key of another table to establish relationships.

Question 6

By adding a primary key, what can we make sure?:

Answer 6

That each record in a table is unique.

Question 7

Name all the entity relationships:

Answer 7

One-to-one
One-to-many
Many-to-many

Question 8

Explain one-to-one,

Answer 8

One-to-one: One record in a table is linked to one record in another table.

Question 9

Explain one-to-many

Answer 9

One-to-many: One record in a table is linked to multiple records in another table.

Question 10

Explain many-to-many

Answer 10

Many-to-many: Records in one table are linked to multiple records in another, often using a bridge table.

Question 11

Advantages of using a primary key:

Answer 11

• Ensures unique identification of records.
• Prevents duplication of data.
• Maintains data integrity.
• Simplifies relationships between tables.

Question 12

Define the term data mining.

Answer 12

Data mining is the process of analysing large sets of data to discover patterns, relationships, or useful insights. It often uses techniques like machine learning, statistics, and database systems.

Question 13

Where is data mining used?

Answer 13

Where it’s used:

Marketing: Identifying customer preferences for targeted advertising.
Healthcare: Finding trends in patient data to predict diseases.
Fraud detection: Spotting unusual patterns in financial transactions.
Retail: Predicting product demand based on past sales.

Question 14

Data Extraction

Answer 14

Definition:
Data extraction involves retrieving specific data from a larger set, usually from databases, documents, or web sources. It prepares raw data for analysis or use in another system.

Question 15

Where is data extraction used?

Answer 15

Where it’s used:

Data migration: Transferring data from old systems to new ones.
Web scraping: Collecting information from websites for analysis.
Document processing: Extracting names, addresses, or invoices from scanned files.

Question 16

Composite Key

Answer 16

Definition:
A composite key is a combination of two or more fields (columns) in a table that together uniquely identify a record.

Example:
Imagine a table tracking students enrolled in courses.

Fields: Student_ID and Course_ID
Individually, neither Student_ID nor Course_ID is unique because students can take multiple courses. But together, Student_ID + Course_ID can form a unique composite key

Question 17

Where do composite keys come in handy?

Answer 17

When no single field is sufficient to uniquely identify a record.
In many-to-many relationships (e.g., students enrolling in courses).

Question 18

Database

Answer 18

Definition:
A database is an organised collection of data that allows for efficient storage, retrieval, and management. It typically consists of tables containing rows (records) and columns (fields).

Question 19

Give examples of databases

Answer 19

Examples:

A banking database stores account information.
A library database tracks books, authors, and borrowers.
A retail database keeps inventory, sales, and customer data.

Question 20

Foreign Key

Answer 20

Definition:
A foreign key is a field in one table that links to the primary key in another table. It establishes a relationship between two tables and ensures data integrity.

Question 21

Example of a foreign key

Answer 21

Example:

Table 1: Customers
Customer_ID (Primary Key)
Table 2: Orders
Customer_ID (Foreign Key)
The foreign key ensures that each order is associated with a valid customer.