DSE Revision: Elective Modules
FoundationPaper 2 examines the modules the school has taken from four electives: Databases, Data Communications and Networking, Multimedia Production, and Software Development. This lesson compares the modules' question styles and revision focuses, and dissects a typical database long question — from table design, primary and foreign keys to redundancy analysis — scoring layer by layer at the marking positions.
- Four modules: Databases, Data Communications and Networking, Multimedia Production, Software Development — sit what the school takes
- Database routine: name redundancy, split into tables, mark keys, explain links; multimedia routine: formula, conversion, format with reasons
- Design questions draw and mark; calculation questions list formula and steps — format itself scores
文體小知識：科技知識說明文——比較四個選修單元的範圍與題型，拆解數據庫典型長題目與評分位，提供卷二的作答格式與最後階段備戰清單。
§Text Passage
1The elective part offers four modules — Databases, Data Communications and Networking, Multimedia Production, and Software Development — with schools generally teaching two, and candidates answer Paper 2 on the modules studied, formats per the HKEAA's latest publications. Choose modules early and change rarely: workloads and question styles differ sharply, and a switch midway means re-learning half a subject. The database and multimedia lessons earlier in this course are exactly the entry foundations of two popular modules.
2Each module revises differently. Databases prize design and querying: tables, primary and foreign keys, normalisation, entity relationship diagrams and basic query language. Multimedia prizes calculation and selection: pixels and resolution, file sizes, lossless versus lossy compression, formats and production stages. Both carry rehearsed routines with clear returns; answers must set out steps and reasons.
3Data Communications and Networking covers network types, devices, protocols and transmission; Software Development covers programming, algorithms and testing. In both, answer with three layers — concept, example, application: the bare term earns only the definition mark, and a scenario-linked explanation earns the application mark. For example, distinguishing a switch from a router requires the layer each works at and its function, then an office and home-networking example; both layers together earn full marks.
4On tactics, Paper 2 long questions are cleanly divided, so read the whole question first and answer part by part, answers matching marks; design questions draw tables and mark keys, calculation questions list steps, evaluation questions argue both sides. In the final stage, drill module papers under time, tabulate the frequent errors, and return to notes. Before the exam, run through each module's winning sheet — must-know terms, must-drill question types, common traps — and enter the hall with confidence.
1Summary 重點摘要
Paper 2 examines the modules the school has taken from four electives: Databases, Data Communications and Networking, Multimedia Production, and Software Development. This lesson compares the modules' question styles and revision focuses, and dissects a typical database long question — from table design, primary and foreign keys to redundancy analysis — scoring layer by layer at the marking positions.
2Vocabulary cards Vocabulary
The part examined in Paper 2, offering four modules according to what the school covers.
An elective module covering table design, keys, normalisation and query languages.
An elective module covering data transmission, network devices and protocols.
An elective module covering image and audio principles, compression formats and production.
An elective module covering programming, algorithm design and testing.
A diagram showing entities, attributes and relationships, common in database questions.
The individual points in the marking scheme that each earn marks.
The movement of data between devices, involving direction and speed.
Data used in software development to check normal, boundary and abnormal cases.
The exam technique of budgeting time according to marks and question types.
3Step by step Steps
- Step 1: The four elective modules at a glanceThe elective part offers four modules: Databases, Data Communications and Networking, Multimedia Production and Software Development; schools generally teach two, and candidates answer on those in Paper 2, formats and weights per the HKEAA's latest publications. For example, School A takes databases and multimedia, School B networking and software development, so their Paper 2 differs entirely. Choose early and change rarely — the routines differ so much that a switch equals re-learning half the course.
- Step 2: Revision focuses of the database moduleThe database module extends lesson one of this course, with four key points: table and key design (primary keys identify uniquely, foreign keys link), normalisation and redundancy analysis, drawing and reading entity relationship diagrams, and basic query language. For example, a typical question shows a table and asks to point out redundancy and rebuild it as three tables; the routine is fixed — name the repeated columns, split by kind of thing, mark the keys, explain the links. With the routine fluent, design questions become gifts.
- Step 3: Revision focuses of the multimedia moduleThe multimedia module centres on calculation and selection. Calculation: image file sizes (pixels times bytes per pixel), unit conversion, animation frame counts. Selection: bitmap versus vector, lossless versus lossy compression, formats and the production stages. For example, a typical question gives a photo's resolution and colour depth and asks for the uncompressed size and a format suggestion; the answer must list the working, convert units and justify the choice — a bare result loses everything if one digit slips.
- Step 4: Key points of the networking and software modulesIf your school takes the other two modules, the key points differ: for Data Communications and Networking — network types and topologies, switches versus routers, transmission media and protocols, addressing concepts; for Software Development — algorithms and flowcharts, control structures, variables and testing. For example, networking questions often give a scenario and ask for equipment with justification: name the device, the layer it works at, the reason — three layers; software questions prize correct flowchart symbols and complete test data. Both carry learnable answer frames.
- Step 5: Answer formats for design and calculation questionsPaper 2 long questions reward format. In design questions, draw the table then mark the keys: line up field names, underline or label the primary key, arrow the foreign keys to their targets. In calculation questions, write the formula then substitute: image size formula and conversions step by step, so a slip at the end keeps the step marks. For example, of two candidates designing three tables, one writes a prose description while the other draws and labels — the labelled table lays every scoring point before the examiner; format itself is a scoring tool.
- Step 6: Arguing both sides in evaluation questionsEvaluation questions demand both sides before a stance. For example, asked whether an organisation should move wholly to a database, list the benefits (less redundancy, access control, consistency), then the costs (expense, training, maintenance), then conclude by scale: large data and many users argue for the move, a single person's few records may not. Writing one side only is the commonest loss; the conclusion must answer the scenario's conditions, never in generalities.
- Step 7: The last-stage module battle sheetBefore the exam, compress each module into a one-page winning sheet: must-know terms (primary key, normalisation, resolution, lossy compression), must-drill types (table design, file-size sums, evaluation frames), common traps (forgetting the byte conversion, formats without reasons, designs without keys). For example, sit one timed module long question daily for thirty minutes, mark it against the marking scheme and correct it; in ten days the answering touch stays sharp, and entering the hall feels steady.
5Worked example Example
Dissecting a typical Paper 2 database long question: A tutoring centre records enrolments in one large table whose rows carry student ID, student name, course ID, course name and tutor name. When a student enrols in several courses, data repeats. (a) Identify the design problem; (b) redesign suitable tables, marking primary and foreign keys; (c) explain how the new design solves the problem. List the answer points and marking positions.
- Read: (a) the problem, (b) the design, (c) the explanation — answer part by part; (b) is a design question, so draw tables and mark keys rather than describe in prose
- Marking points for (a): name data redundancy — names and course details repeat with every enrolment — and note the inconsistency risk, such as renaming a tutor touching many rows
- The design: Student table (primary key Student ID, with name), Course table (primary key Course ID, with course name and tutor name), Enrolment table (primary key Enrolment ID or the key pair, with Student ID and Course ID as foreign keys)
- Marking points for (c): each item stored once so one update touches one place; the Enrolment table's two foreign keys link the tables and express one student taking many courses
- Self-check the marking positions: key terms hit (redundancy, primary key, foreign key), tables and keys clearly marked, explanation tied to the scenario — all three present
- Answer: (a) The original table mixes three kinds of things — students, courses, enrolments — in one table: a student enrolled in several courses repeats the name each time, and course names and tutor names repeat with every enrolment; this is data redundancy, and a missed update, such as a tutor renaming, produces inconsistency. (b) Design three tables: the Student table with Student ID as primary key holding the name; the Course table with Course ID as primary key holding course name and tutor name; the Enrolment table recording the enrolment relation, with Student ID and Course ID as foreign keys pointing to the other two tables. (c) In the new design every item is stored once: a renaming touches only the Student table, a tutor change only the Course table; the Enrolment table links the two through its foreign keys, and one student taking many courses is simply more rows — solving redundancy and inconsistency together. Marking points: (a) naming redundancy, (b) three tables with correct keys, (c) explanation tied to repetition and updates — missing any loses its marks.
6Common mistakes Mistakes
7Quick check Quick check
Q1Which four modules does the elective part offer?
Q2What are the four revision focuses of the database module?
Q3Which steps do multimedia calculation questions involve?
Q4What does the answering format of a design question require?
Q5What is the structure of an evaluation answer?
8Recap Recap
- Four modules: Databases, Data Communications and Networking, Multimedia Production, Software Development — sit what the school takes
- Database routine: name redundancy, split into tables, mark keys, explain links; multimedia routine: formula, conversion, format with reasons
- Design questions draw and mark; calculation questions list formula and steps — format itself scores
- Evaluation questions argue both sides then conclude by the scenario's conditions
- A one-page winning sheet per module: must-know terms, must-drill types, common traps; timed drills keep the touch