CodeIEB
Theory Notes/🗄️ Topic 4: Data & Information Management, Solution Development/12.4.9
12.4.9Grade 12

Storing, Protecting & Retrieving Data

Zooming out from a single database to enterprise-scale data concepts: threats to data quality, data warehousing, data mining, big data, and NoSQL.

Threats to data quality:

ThreatDescription
Corrupted dataData that has been damaged/altered unintentionally, often becoming unusable or inaccurate
Outdated dataData that was once accurate but is no longer current
Invalidated dataData that hasn't passed proper validation checks and may not meet expected rules
VulnerabilityWeaknesses that expose data to attack, e.g. SQL injection (malicious code inserted via input) or malware infections
Data warehousing
The process of collecting and consolidating data from multiple different sources into one large, central repository, specifically structured to support analysis and reporting rather than day-to-day transaction processing.
Data mining
The process of analysing large datasets (often from a data warehouse) to discover patterns, trends, and useful relationships that inform decision-making.

Purpose and uses: data warehousing consolidates historical data for large-scale analysis; data mining extracts actionable insights and patterns from that consolidated data.

Big data — sources include social media, activity-generated data (e.g. app usage logs), server logs and audit trails, and location-based data (GPS/LBS).

NoSQL
A category of database systems that don't rely on the traditional fixed-table, relational structure of SQL databases — instead often using flexible document, key-value, or graph-based structures, e.g. MongoDB (a document-based NoSQL database).
ComparisonSQL (relational)NoSQL
StructureFixed schema, structured tables with defined relationshipsFlexible, often schema-less — good for varied/changing data shapes
ScalabilityTraditionally scales vertically (more powerful single server)Often designed to scale horizontally (many distributed servers) — well suited to big data
Best forStructured data with clear relationships, requiring complex queries/joinsLarge volumes of unstructured/semi-structured, rapidly changing data

💡 Exam Tip

The SQL vs NoSQL comparison is a common essay-style question — anchor your answer around structure (fixed schema vs flexible) and scalability (vertical vs horizontal), which are the two clearest, most defensible distinguishing factors.