QCAA Digital Solutions cheat sheet

A relational database stores data in tables (relations); each row is a record and each column is an attribute with a defined data type.

Primary key uniquely identifies each record in a table; a foreign key is an attribute in one table that references the primary key of another table to enforce referential integrity.

Normalisation stages: 1NF removes repeating groups so each cell holds one atomic value; 2NF removes partial dependencies on part of a composite key; 3NF removes transitive dependencies on non-key attributes.

SQL clauses execute in the logical order FROM → WHERE → GROUP BY → HAVING → SELECT → ORDER BY; HAVING filters aggregated groups while WHERE filters rows before grouping.

Aggregate functions COUNT, SUM, AVG, MIN and MAX collapse many rows into one value; without GROUP BY they return a single row for the whole table.

INNER JOIN returns only rows with matching keys in both tables; LEFT JOIN keeps all rows of the left table and fills unmatched right-side columns with NULL.

Data types matter: INTEGER for whole numbers, REAL/DECIMAL for fractions, TEXT/VARCHAR for strings, DATE for calendar values; a mismatched type can block sorting or arithmetic.

A data flow diagram models processes, data stores, external entities and data flows; a context diagram is the single-process level-0 view of the whole system.

Software development approaches: waterfall is sequential with fixed requirements; agile is iterative with short sprints and continuous stakeholder feedback.

A minimum viable product (MVP) delivers only core features to test demand early; prototyping builds a working model to clarify requirements before full build.

Version control stores every change as a commit, allows branching for parallel work, and merging integrates branches; a repository is the tracked project store.

Testing levels: unit tests check one component, integration tests check component interaction, system tests check the whole system, and acceptance tests check user requirements.

Intellectual property protection: copyright covers original code and content automatically, patents protect novel inventions, trademarks protect branding, and trade secrets rely on confidentiality.

A privacy impact assessment identifies personal data collected, its purpose, storage, access and disposal, aligning with Australian Privacy Principles.

Accessibility principles (WCAG POUR): content must be Perceivable, Operable, Understandable and Robust, including text alternatives and keyboard navigation.

Evaluation criteria for a digital solution include functionality, usability, efficiency, maintainability, security and sustainability, each judged against stated requirements.

The external assessment is a written exam combining multiple-choice and short/extended response; questions target the cognitive verbs define, describe, explain, analyse and evaluate.

Command verbs set depth: describe states features, explain gives reasons and cause-effect, analyse breaks into components and relationships, evaluate judges against criteria with a recommendation.

Extended responses are marked against criteria; a judgement or recommendation with justified evidence scores higher than a description of features.

When asked to write or interpret SQL, name tables and columns explicitly and state the join condition; ambiguous column names lose marks.

Structured questions often supply a scenario; answers must reference the scenario's entities, users or constraints rather than generic textbook statements.

Calculations such as storage size (files × size × copies) or data transfer time (size ÷ rate) require units shown and consistent conversion (1 GB = 1024 MB).

For 'analyse impacts' questions, address both positive and negative effects and identify at least one stakeholder group affected.

Diagrams are marked on labelled components and correct relationships; an unlabelled box or arrow earns little credit regardless of shape accuracy.

Multiple-choice items test recall and simple application; eliminate options that misstate a definition or reverse a cause-effect relationship.

Short-response items of 2–4 marks usually require one distinct idea per mark; state the idea explicitly rather than implying it.

Extended-response items of 6+ marks reward structure: an introduction stating the position, body paragraphs each making one point with evidence, and a conclusion.

Marking uses a criteria sheet; each criterion is judged independently, so a strong evaluation can still score even if the description criterion is weak.

When a question supplies data or a table, quote specific values from it in the response to demonstrate application rather than general knowledge.

Time allocation should follow marks: roughly one minute per mark, leaving time to check that every question has an attempt.

If a question asks for a recommendation, name the chosen option, give at least two reasons tied to criteria, and acknowledge one limitation.