WEEK 8 - INTRODUCTION TO DATABASES

Question 1

What is a database?

Answer 1

• a collection of data organized to serve many applications simultaneously by storing and managing data so they appear to be in one location

Question 2

purpose of databases?

Answer 2

• to efficiently store, manage, and retrieve large volumes of data
• to minimize redundancy and ensure data integrity and consistency
• to facilitate multi-user access and distributed access to data

Question 3

components of databases

Answer 3

• tables: organized into rows (records) and columns (fields/attributes)
• fields: characteristics or properties of the data
• records: instances of data entries

Question 4

why do we need databases?

Answer 4

• data volume: the amount of business data increases every year, including sales, purchases, salary activities, client enquiries
• business intelligence: databases store transaction data that can be analyzed to produce valuable business intelligence
• efficiency: databases minimize redundancy and enable efficiency data retrieval and management

Question 5

example of data base in toy store

Answer 5

• customer data: customer ID, name etc
• sales agent data: agent ID, name etc
• order data: order ID, date etc
• product data: toy ID, name, price etc

Question 6

how do relational databases work?

Answer 6

• organize data into tables that are related to each other
• each table represents an entity (eg. customer, sales, product)
• use of keys to establish relationships between tables

Question 7

what is a primary key in relational databases?

Answer 7

• a unique identifier for each record in a table

Question 8

what is a foreign key in relational databases?

Answer 8

• a field that links one table to a primary key in another table

Question 9

define normalization in relational databases?

Answer 9

• process of organizing data to minimize redundancy and improve data integrity
• first normal form (1NF): data stored in tables without repeating groups
• second normal form (2NF): 1NF plus all non-key attributes depend on the entire primary key
• third normal form (3NF): 2NF plus no transitive dependencies

Question 10

example of normalization

Answer 10

• customer table: contains customer details
• order table: contains order details, linked to the customer table via a foreign key
• product table: contains product details, linked to the order table via a foreign key

Question 11

function of database management systems (DBMS)

Answer 11

• software for creating, storing, organizing and accessing data from a database
• provides tools for data definition, querying and reporting

Question 12

capabilities of database management systems (DBMS)

Answer 12

• data definition: specify the structure of the database
• data dictionary: stores definitions of data elements and their characteristics
• querying and reporting: use of SQL for data manipulation and extraction

Question 13

SQL example:

Answer 13

• retrieves clients with debts greater than $1000
• SELECT Clientname, Debt FROM Client WHERE Debt > 1000

Question 14

define cloud databases

Answer 14

databases hosted on cloud services, offering scalability and flexible pricing

Question 15

define distributed databases

Answer 15

• databases stored in multiple physical locations, providing consistency and reliability

Question 16

define blockchain

Answer 16

• a decentralized database maintaining a growing list of record called blocks
• enhances security and reduced transaction costs

Question 17

compare blockchain and relation databases

Answer 17

• relational databases are centralized and managed by an administrator
• blockchain is decentralized with no central control, offering high data integrity and transparency