IT Theory Grade 12 - Flashcards (Question and Answer)

A set of Question-and-Answer flashcards covering key concepts from IT Theory Grade 12 notes, including databases, data warehousing/mining, data quality, security, cloud services, and networking.

What does DBMS stand for and what is its role?

Database Management Software; software responsible for creating, maintaining and administering databases, including managing data security and access (examples: Microsoft SQL Server, Microsoft Access, MySQL, SQLite).

What is data warehousing?

A technique for storing data from more than one database in a non-normalised form, often containing redundancies, designed to make data available for analysis and business intelligence.

How does a data warehouse differ from a database?

A data warehouse stores historical data from multiple sources for analysis; a database stores current transactions for ongoing business processes.

Define a primary key in a database.

A field that holds a unique identifier for each record in a table, enabling precise identification and referential integrity.

What is data mining?

A process to identify trends and patterns in large databases (big data) to extract knowledge for better decision making.

List the three main steps of the data mining process.

1) Extract the relevant data, 2) Look for patterns in the data, 3) Discover knowledge from the patterns.

Name the five characteristics of high-quality data.

Accurate, Consistent, Current, Complete, Relevant.

Differentiate data validation from data verification.

Data validation checks data at entry for correct format/type; data verification manually checks accuracy (full or sample).

What is an audit trail in databases?

A record of who changed data, what was changed, and when the changes were made.

Define data redundancy and why it is a problem.

Storing the same data in multiple places; wastes space and can cause integrity problems and anomalies.

What is First Normal Form (1NF) in database design?

A table must have atomic column values, each column has a unique name, and values in a column are of the same type; no repeating groups.

What does 2NF imply about dependencies?

The table is in 1NF and has no partial dependency—no non-key attribute depends on only part of the primary key.

What does 3NF require?

The table is in 2NF and has no transitive dependency—non-key attributes do not depend on other non-key attributes.

How is data warehousing linked to business intelligence (BI)?

Data warehousing is a key BI tool used to improve business decision making by enabling analytics across multiple data sources.

What is a cookie in web technologies?

A small text file stored by a browser that identifies users and can store preferences for personalization.

What is location-based data (LBS)?

Data that provides information about a user’s location (GPS-based); used in services like weather, ride-hailing, and mapping.

What does RFID stand for and what is its use?

Radio Frequency Identification; tiny chips storing data that can be scanned by readers to identify and track items.

Why is a data warehouse often denormalised?

To optimise analytics and reporting by reducing the need for complex joins, though it may introduce redundancy.

Differentiate data and a database’s basic terms 'field' and 'record'.

Field is a single attribute/column; a record is a row containing related fields.

What is a VPN and its purpose?

Virtual Private Network; a private network over the internet that encrypts traffic and allows secure access to private resources.

What is SaaS?

Software as a Service; cloud-hosted applications accessed via a web browser; users pay a subscription and do not own the software.

What is cloud computing?

Providing computing resources (storage, processing, applications) over the internet; scalable, affordable, reliable and maintained by providers.

Explain SSL and its certificates.

SSL (Secure Sockets Layer) encrypts data in transit; certificates from a Certification Authority prove a website’s identity and enable trusted encryption.

What is a firewall?

A security device/software that blocks unauthorized network access; can be software, hardware, or a combination.

Define BitTorrent.

A peer-to-peer file sharing method where pieces of a file are shared among many peers to speed up distribution.