Theory Notes/🗄️ Topic 4: Data & Information Management, Solution Development/11.4.9

11.4.9Grade 11

Purpose & Features of a DBMS

Stepping back from writing SQL to understand the software (a Database Management System) that actually manages the database underneath your queries.

DBMS (Database Management System): Software that creates, manages, and controls access to a database, sitting between the actual stored data and the applications/users that need to use it.

Data integrity management — the DBMS helps ensure data quality across several dimensions:

Dimension	Meaning
Accuracy	The data correctly reflects reality
Correctness	The data conforms to the rules/constraints defined for it
Currency	The data is up to date
Completeness	No required data is missing
Relevance	The data stored is actually needed/useful

Security functions of a DBMS:

Multiuser access control — managing which users can access/modify which data.
Encryption — protecting stored data from being read if accessed without authorisation.
Awareness of design flaws and programming bugs that could expose data.
Protection against SQL injection — a technique where malicious SQL code is inserted through user input to manipulate or damage the database.
Protection against malware infections targeting the database server.

Backup, recovery and management — a DBMS typically provides tools to back up data regularly and recover it after a failure or corruption event.

💡 Exam Tip

SQL injection is a favourite short-answer question: know that it happens because user input is inserted directly into a SQL command without proper validation/sanitisation, and that the defence is validating/escaping user input before using it in a query.