Core Data Concepts

Question 1

Why has data exploded recently?

Answer 1

Because modern apps, devices, and systems produce huge amounts of data.

This explosion is driven by the increasing number of connected devices and applications.

Question 2

Why is it easier to collect data today?

Answer 2

Storage is cheaper and tools are more advanced.

Advances in technology have made data collection more efficient and cost-effective.

Question 3

Why do businesses depend on data?

Answer 3

• To make decisions
• Improve revenue
• Gain competitive advantage

Data-driven decision-making is crucial for modern business success.

Question 4

What is data?

Answer 4

Facts about something.

Data serves as the foundation for analysis and decision-making.

Question 5

Give four examples of data entities.

Answer 5

• Customers
• Products
• Sales
• Orders

These entities represent key components of business operations.

Question 6

What are attributes?

Answer 6

Details describing an entity (e.g., name, price, address).

Attributes provide specific information about data entities.

Question 7

What is structured data?

Answer 7

Data organised in tables with rows and columns.

Structured data is easily searchable and analyzable.

Question 8

Where is structured data usually stored?

Answer 8

Relational databases (SQL).

SQL databases are designed to handle structured data efficiently.

Question 9

What is semi-structured data?

Answer 9

Data with some structure but flexible (e.g., JSON).

Semi-structured data allows for more variability than structured data.

Question 10

What is unstructured data?

Answer 10

Data with no fixed format (images, PDFs, videos, emails).

Unstructured data is more challenging to analyze due to its lack of organization.

Question 11

What are the two big storage categories?

Answer 11

• Files
• Databases

These categories encompass the primary methods for storing data.

Question 12

What are CSV/TSV files good for?

Answer 12

Structured, table-like data.

These formats are commonly used for data interchange.

Question 13

Why is JSON popular?

Answer 13

It’s flexible and hierarchical.

JSON is widely used for data interchange in web applications.

Question 14

What type of data is stored in binary files?

Answer 14

• Images
• Audio
• Video

Binary files are used for non-text data types.

Question 15

Name three optimised big-data formats.

Answer 15

• Avro
• ORC
• Parquet

These formats are designed for efficient storage and processing of large datasets.

Question 16

What do relational databases store?

Answer 16

Tables of organised data.

Relational databases use structured query language (SQL) for data manipulation.

Question 17

What prevents data duplication in SQL databases?

Answer 17

Normalisation.

Normalisation is a process to reduce redundancy in database design.

Question 18

What language is used to query relational databases?

Answer 18

SQL.

SQL stands for Structured Query Language.

Question 19

What is a key characteristic of NoSQL databases?

Answer 19

They do NOT use traditional tables.

NoSQL databases are designed to handle unstructured and semi-structured data.

Question 20

Give an example of a key-value database.

Answer 20

Redis.

Key-value databases are known for their simplicity and speed.

Question 21

Give an example of a document database.

Answer 21

MongoDB.

Document databases store data in document formats like JSON.

Question 22

Give an example of a column family database.

Answer 22

Cassandra.

Column family databases are designed for high scalability.

Question 23

Give an example of a graph database.

Answer 23

Neo4j.

Graph databases excel in managing relationships between data points.

Question 24

What is OLTP used for?

Answer 24

Real-time business operations (orders, bank transfers).

OLTP stands for Online Transaction Processing.

Question 25

What do the **ACID rules** ensure?

Answer 25

* Correct * Reliable * Consistent transactions ## Footnote ACID is an acronym for Atomicity, Consistency, Isolation, Durability.

Question 26

What is **OLAP** used for?

Answer 26

Analytics, reporting, dashboards. ## Footnote OLAP stands for Online Analytical Processing.

Question 27

What type of data does **OLAP** typically use?

Answer 27

Large amounts of historical data. ## Footnote OLAP systems are designed for complex queries and analysis.

Question 28

What is **ETL**?

Answer 28

Extract, Transform, Load. ## Footnote ETL is a process used to integrate data from multiple sources.

Question 29

What is a **Data Lake**?

Answer 29

Raw file-based storage for flexible analysis. ## Footnote Data lakes can store structured and unstructured data.

Question 30

What is a **Data Warehouse**?

Answer 30

Structured, relational storage designed for BI and fast SQL queries. ## Footnote Data warehouses are optimized for reporting and analysis.