QCE Digital Solutions Unit 3 — Interactions Between Users, Data and Digital Systems Hangman

The 146 key terms

1Need or opportunity

A problem worth solving or a gap worth exploring, forming the starting point for developing a digital solution

2disruptive solution

A solution that significantly challenges or replaces existing products, services or ways of doing things — transforming an industry or creating an entirely new market

3enterprise opportunity

A gap in what people need that a solution could fill, plus a way to deliver it to a target market, such as selling an app to students who have no good option yet.

4gap in the market

A need that no existing product meets well, so an individual or business builds new software to serve a target market and take advantage of competitor weaknesses.

5productivity and efficiency

A reason to build software: do more work in less time or effort by automating manual tasks, cutting errors and rework, and speeding up processing.

6community impact

How a digital solution affects other people, not just its user. It can help (benefits), cause problems (harms), or leave some people out.

7assistive technology

A digital system designed to help people with disabilities perform tasks that would otherwise be difficult or impossible, such as screen readers, hearing aids and communication devices

8future impact

How a solution could affect society, the economy and the environment over time, including unintended effects its designer did not plan for.

9Ethical issue

A situation where a design or technology choice could unfairly harm, exclude, or disadvantage people, even if it is legal

10digital system

A combination of hardware and software that inputs, processes, stores and outputs data for a purpose, such as a laptop, tablet, smart speaker or games console.

11input, process, store, output

A digital system takes in data (input), works on it (process), keeps it (store) and shows a result (output).

12purpose and user

Every digital system is made to do a job (its purpose) for certain people (its users). Example: a school library system helps students and teachers borrow books.

13components work together

Hardware and software cooperate in a sequence, such as input device, operating system, CPU, then output, to finish one user action like a mouse click or saving a file.

14trace an action

Follow one action, like a game tap: the screen senses it, the CPU decides, RAM holds the game, storage keeps the saved score and the screen shows the result.

15control mechanism

Decides what a system does next. Open loop ignores the result (a timer); closed loop uses a feedback signal from the result (a thermostat).

16analytical tools

Diagrams like context, data flow and use case diagrams that show how users, data and systems relate, so the existing system is understood before a solution is designed.

17Depicting an existing system

Using analytical tools like context and data flow diagrams to show how the current system works, so bottlenecks and problems are exposed for the new solution to fix.

18IPO chart

A three-column table listing a solution's inputs (data entered), the processes applied to that data, and the outputs it produces, such as a total or report.

19flowchart

A diagram that uses an oval for start and end, a rectangle for a step and a diamond for a yes or no question, all joined by arrows that show the order.

20decision diamond

A diamond shape in a flowchart that asks a yes or no question. One arrow is labelled Yes and one is labelled No, and each arrow leads to different steps.

21loop arrow

An arrow that goes back to an earlier shape so steps repeat. The loop stops when the decision's exit arrow is followed, such as when the answer is Yes.

22context diagram

A Level 0 diagram that shows the whole system as one process in the centre, with external entities around it outside the system boundary.

23data flow

A labelled arrow on a context diagram showing data passing between an entity and the system. The arrowhead shows direction (input or output) and the label names the data.

25Level 1 DFD process

A numbered, named step (e.g. 1.0 Validate Order) in a Level 1 DFD. It uses a verb phrase and shows one main task from the context diagram's single system.

26Data store

On a Level 1 DFD, a data store is where data is held (e.g. a file or database). Entities sit outside the system and send or receive data. Both must match the context diagram.

28Level 1 DFD

Breaks a system into processes, data stores, entities and labelled flows found in a scenario, then checks the rules, e.g. every process has an input and an output and no flow is missing.

29web application

Software run through a browser, made of server-side parts (web server, database server, server-side code) and client-side parts (browser, user device) that connect over the internet.

30client-server

A client, like your browser, sends a request for data and a server stores that data and sends a response back.

31web server

A computer that stores website files and sends them to a browser (the client) over the internet using HTTP when the browser asks for a page. It is always switched on and connected.

32database server

A computer or program that stores a database and answers queries sent by other programs, such as a web server, by returning the matching data while keeping the stored data protected.

33server-side code

Code that runs on the web server, not the browser. It handles a request, processes form data, queries the database and builds the response sent back to the client.

34web browser

Software that requests web pages from web servers and displays them to the user, e.g. Chrome, Firefox, Safari or Edge. It is the client, and it is not a search engine.

35HTTP request

A message the browser sends to the web server's IP address asking for a page; the server replies with the page's HTML, or an error such as 404 if it does not exist.

36rendering

Rendering is when the browser reads the HTML it received and paints it into the visible page shown on screen.

37HTTP request and response

The browser sends an HTTP request asking for a page. The web server sends back an HTTP response with the page's HTML, or an error such as 404 page not found.

38URL -> DNS -> IP -> server -> HTML -> render

The ordered steps after you enter a URL: the browser asks DNS for the IP address, sends a request to the web server, gets HTML back, then renders the page.

39web page layers

Every part of a page is content (words, images), structure (tags), presentation (CSS colour, layout) or behaviour (JavaScript). Each layer can be changed on its own.

40JavaScript

The programming language that adds behaviour to a web page, such as reacting to a click, on top of its HTML content and structure and its CSS presentation.

41action

The <form> attribute that specifies the URL where the form data is sent when the user submits. Without it, data is sent to the current page URL.

42API

An application programming interface: a defined set of requests and responses that lets one program use the features or data of another program.

43requests.get(url)

Sends a request to a web API endpoint at the given URL and returns a response object. Needs import requests. Check response.status_code (200 means success) before using the data.

44response.json()

Converts the JSON text of an API response into Python dictionaries and lists, so you can read values by key, e.g. data['name'], or loop over a list of results.

45one-dimensional array

A named, ordered collection of elements of the same data type. Each element is reached by its index, its position number (0-based in Python, often 1-based in pseudocode).

51record

A data structure that groups related fields of different data types into one item describing one thing, e.g. a student's name (String), age (Integer) and enrolled (Boolean).

52list, dict, tuple

Pick the structure by how you use the data: a list for an ordered collection, a dict for lookup by key, and a tuple for a fixed group of values that should not change.

53app components

The parts that make up a mobile app: interface controls on screens, objects with data and behaviour, event handlers that respond to the user, and libraries of ready-made code.

54GUI

A graphical user interface: windows and controls like buttons and text boxes the user clicks or types in. The program waits for events, such as a click, and responds to each one.

55tk.Label(root, text='...')

Creates a tkinter label that shows text in the window. Use .config(text=...) to change what it shows, such as displaying a result. Options like font and fg set style.

56entry = tk.Entry(root)

Creates a text box in the window. Call entry.get() to read what the user typed. It is always a string, so convert it with int() or float() to use it as a number.

57tk.Button(root, text='Go', command=show)

Makes a button that runs the function show when clicked. Write the function name with no brackets, or it runs straight away instead of on click.

58StringVar()

A tkinter variable that stores the user's pick from a choice control (Checkbutton, Radiobutton or Combobox). Link it with variable= and read the choice with .get().

59control.grid(row=0, column=1)

Places a control in a table-like layout at the given row and column. pack() instead stacks controls in order. Never mix grid and pack in one window.

60messagebox.showinfo()

Pops up a message window to tell the user a result. Its partner messagebox.showerror() pops up an error, such as when a handler finds invalid input. Both need a title and a message.

62library

A collection of ready-made code you can reuse. The standard library comes with Python; third-party libraries are made by others and must be installed separately (e.g. with pip).

63pip install requests

A terminal command that uses pip to download a third-party library (here requests) so a Python program can then import it. Add ==2.31.0 after the name to pick a version.

64third-party dependency

A library written by someone else that your program imports and relies on. A flaw in it affects every app that uses it, and it may pull in its own dependencies too.

65user flow

The path of screens a user follows to finish a task, like logging in or buying a ticket. Navigation controls such as back and home buttons help them move along it in as few steps as possible.

66App permissions

Settings where each app asks to use your location, camera, microphone or contacts. You can allow or deny each one, or allow only while using the app, and review them any time.

67emerging digital tool

A new or fast-changing technology, like an AI assistant, online whiteboard or interactive-video maker, that creators use to make and share content in new ways.

68fit for purpose

Choosing a tool because its features match what the content must do and who will use it, then justifying the choice with reasons like ease of use, device support and cost.

69<video controls>

The <video> element embeds a video in a page. Its src attribute gives the file, and controls adds play and pause buttons. The <audio> element works the same way for sound.

70<a href="page2.html">

A link that jumps the viewer to another page or section when clicked, so they choose their own path through interactive content. Use #id to jump to a section.

71captions and transcript

Captions show spoken words as on-screen text. A transcript is the full text of audio or video. Both help deaf, hard-of-hearing and no-sound viewers. Always check auto-captions.

72interactive prototype

A clickable model of a design where buttons link screens together, so users can try a task before any code is written. It is used for testing, not the final product.

73user testing

Watching real members of your audience use your content on a phone and a computer, then recording what confused them and what to change.

74automated system

A system that senses its surroundings, decides what to do and acts, without a person controlling each step. For example, an automatic door.

75sensor

An input device that measures a physical quantity, such as heat or light, from the environment and sends the readings to a computer or microprocessor.

76data first, then sensor

Each sensor captures one type of data, so identify the data first (e.g. moisture in soil, humidity in air), then name the sensor that measures it.

77ADC (analogue-to-digital converter)

Turns the continuously varying analogue readings from a sensor into digital values (binary numbers) so a computer can process them.

78microprocessor

A CPU built as an integrated circuit on a single chip. It is only the processor, not the whole computer, and is found in PCs, phones and embedded devices.

79stored value

A pre-set value, such as a target temperature, kept in the microprocessor. It compares each digital sensor reading with it to decide if the reading is too high, too low or on target.

80actuator

An output device that turns a control signal from a processor into physical action, such as a motor turning, a valve opening or a heater switching on, in control systems and robots.

81feedback

When an actuator's effect changes the next sensor reading, so the system keeps adjusting itself until the stored value is reached, e.g. a heater warms the room until the target.

82feedback loop

A sensor sends readings to a microprocessor, which compares them with a stored value and signals an actuator, such as a heater, to act. This repeats continuously.

83input device

A piece of hardware, like a keyboard, mouse, microphone, camera, scanner, sensor or touchscreen, that sends data into a digital system.

84output device

A piece of hardware that shows or gives the results of processing to the user, such as a monitor, projector, speakers, headphones or printer.

85analogue vs digital

Analogue signals vary smoothly over a range; digital signals have fixed values like on/off (1/0). Systems convert between them, e.g. ADC at a sensor input, DAC at a speaker output.

86speaker

An output device that turns an electrical signal into sound. An electromagnet makes a cone vibrate, and the vibrations make sound waves. A DAC first converts digital sound to analogue.

87inputs and outputs

A complete system uses input devices or sensors to capture data and output devices or actuators to deliver results, each chosen to suit the task.

88sensor, microprocessor, stored value, actuator

Describe the system: the sensor measures, the microprocessor compares the reading with a stored value, the actuator responds, and the process repeats.

89SQL

Structured Query Language, the standard language for asking a database to return data (SELECT) or to add, change or remove it (INSERT, UPDATE, DELETE).

90relational database

A database that stores data in separate tables of fields (columns) and records (rows), with tables linked by shared values such as keys.

91table, query, form, report

The four database objects: a table stores records, a query finds records, a form enters records and a report presents them.

92data type

The kind of value a database field accepts, such as text, number, date or yes/no. It stops the wrong kind of data being entered, like words in a number field.

93PRIMARY KEY

A field whose value is unique for every record in a table, such as a student ID number, so each record can be identified exactly. Names make poor keys because they can repeat.

94entity

A type of thing a database stores data about, such as a student, book or order. Each entity becomes one table, and its name is a singular noun.

95attribute

An attribute is one property of an entity, like a student's name or year level. Each attribute becomes one field (column) in the entity's table, and each instance of the entity is one record.

96CREATE TABLE

SQL command that builds a new table by naming its fields and their data types, such as a PRIMARY KEY. INSERT INTO ... VALUES then adds one record to that table.

97SELECT name, age FROM students;

SELECT lists the fields to show and FROM names the table. This returns the name and age columns for every record in students. SELECT * shows all columns. End with a semicolon.

98WHERE

An SQL clause that keeps only the rows meeting a condition, such as WHERE age >= 15 or WHERE town = 'Perth'. Text goes in quotes, and AND or OR can combine conditions.

99data redundancy

The same details stored again and again in one big table. It wastes space and risks typos or missed updates, like a customer's address copied onto every order.

100anomaly

A fault caused by redundant data: an update anomaly leaves copies that disagree, an insertion anomaly blocks adding data, and a deletion anomaly loses other data when a record is removed.

101normalisation

Splitting a table so repeated details move into their own table, linked back with a foreign key, so each fact is stored only once and redundancy is reduced.

102FOREIGN KEY

A field in one table that holds the primary key value of a record in another table, linking the two tables together so related data is stored once and not repeated.

103one-to-many relationship

One record in a primary table matches many records in a related table. The foreign key sits on the many side, e.g. one class has many students, so class details are not repeated.

104junction table

A table that splits a many-to-many relationship into two one-to-many links by holding two foreign keys, such as Enrolment with studentId and subjectId.

105ERD

An entity relationship diagram draws each entity as a labelled box and each relationship as a line joining two boxes. Boxes list attributes, with PK and FK marked.

106crow's foot

ERD notation where a single bar at a line's end means one and a three-pronged crow's foot means many. The crow's foot end is the foreign key side of the relationship.

107ERD from a scenario

Find the entities, list their attributes, pick primary keys, then work out each relationship and draw it, with the foreign key on the many side.

108referential integrity

Every foreign key value must match an existing primary key in the related table, so no record points to something missing. The database blocks changes that break this.

109FOREIGN KEY (field) REFERENCES other_table(field)

Used in CREATE TABLE to link a column to another table's key. The database then only accepts values that match an existing key, so bad links are rejected.

110JOIN

A join matches each foreign key value in one table to the primary key value in another, so rows from both tables show together. Rows with no match are left out.

111ON orders.customer_id = customers.customer_id

The join condition: it matches the foreign key in one table to the primary key in the other. The = sign compares the two values to find matching rows. It does not assign a value.

112table.field

Names the table a field comes from, like students.name. Needed in a join when both tables share a field name, or SQL gives an ambiguous column error.

113FROM students s

Gives the students table the short name s after FROM, so the rest of the query can write s.firstName instead of students.firstName.

114JOIN ... ON ... WHERE ... ORDER BY

After JOIN ... ON links two tables, WHERE filters the joined rows and ORDER BY sorts them. Clause order: SELECT, FROM, JOIN ON, WHERE, ORDER BY.

115JOIN subjects ON results.subjectId = subjects.subjectId

A second JOIN line chained after the first to reach a third table. It follows a foreign key in the junction table to the primary key of the next table.

116Cartesian product

A join with no ON condition pairs every row of one table with every row of the other, so 3 customers and 4 orders give 12 rows, most of them wrong.

117multi-table query

A query that gets fields from more than one table: find which tables hold them, JOIN them on matching keys, then add WHERE and ORDER BY to match the question.

118Agile development

Building a solution in short repeating cycles (sprints), releasing working parts and adapting to user feedback and changing requirements.

119waterfall development

A method where each stage (requirements, design, build, test, release) is finished in fixed order before the next starts, with little change once done, so late changes cost more.

120iteration

Making a version, testing it, getting feedback and improving it, then repeating the cycle until it does its job. Save numbered versions and change one thing at a time.

121iterative project

A project done in short repeating cycles of plan, build, test and review. Feedback from each cycle is used to update the task list and schedule for the next one.

122Kanban board

A board where each task is a card that moves through columns like To do, Doing and Done, so the whole team can see the project's status at a glance.

123Proof-of-concept, Prototype, Product

Three progressive stages of solution development: proof-of-concept tests feasibility, prototype demonstrates function, and product is the final polished release

124user-centred design

Designing a solution around the needs of its real users, by finding out what they need and involving them throughout development, using their feedback to revise the design.

125proposed users

The people a brief names as expected to use the software, with their skills and needs, so the design can suit them.

126different users, different needs

One digital system can suit one user well and fail another, because users differ in age, ability and experience. Features like read-aloud and large text help.

127prioritising requirements

Ranking requirements as must-have, should-have or nice-to-have so the most important needs are built first, and trade-offs are made when time or budget is limited.

128development method

Choosing the approach by weighing how clearly users state requirements, how involved they can be and how often needs change: agile if engaged, waterfall if stable.

129alpha testing

Testing run by the developer during development to check the solution meets requirements and works correctly, so errors are found and fixed before beta testing with users.

130beta testing

Testing where potential users try the near-finished solution to check it meets requirements and is usable. It follows alpha testing, which is done by the developers.

131useability principles

Six criteria for judging an interface: accessibility, effectiveness, efficiency, error tolerance, engagement and ease of learning. Each feature of a design can be matched to one of them.

132accessibility features

Design choices like alt text, captions, keyboard-only controls, adjustable text size and not relying on colour alone, so people with different abilities can use a system.

133Effectiveness

How well a solution does what it was meant to do, giving correct, complete and usable results that meet the requirements and suit its purpose.

134efficiency

How well a solution uses resources such as time, processing, memory, storage and user effort to do its job. An efficient solution is fast, light on memory and storage, and saves the user time.

135error tolerance

A useability principle: the interface prevents mistakes where it can, and helps users notice and recover from the ones they make, using validation, confirmation prompts and undo.

137ease of learning

A useability principle: a new user can work out how to complete tasks quickly without training, helped by familiar conventions, clear labels and onboarding hints.

138engaging

An engaging interface is pleasant and motivating to use, through visual appeal, interactivity and rewards, so users want to keep using it.

139usability

How easily, quickly and accurately users can learn and use software to achieve their goals, including ease of learning, efficiency of use, and error prevention and recovery.

140line, shape, texture

Building-block design elements combined with colour, type and space: lines lead the eye, shapes give meaning and texture adds depth.

141colour palette

A small, consistent set of colours where each colour has one meaning. Use the same colour for the same category, and never rely on colour alone, so colour-blind viewers can still read it.

142font hierarchy

Using only two or three fonts, with size and weight showing importance from title to heading to body to caption, so a visualisation is easy to read.

143icon

A small simple picture that makes a topic quick to recognise. Keep icons relevant and in one style, use them only where they help the data, and credit or get permission for any you borrow.

144alignment

A UI design principle that lines up elements along common edges or centres, such as a left edge or grid, so the layout looks tidy and is easy to scan.

145balance

The even spread of visual weight across a screen so no side feels too heavy. It can be symmetrical (mirrored) or asymmetrical (different elements that still feel equal in weight).

146contrast

The difference in colour, size or brightness that makes key elements and text stand out from their background so they are easy to read and notice.

147space

The empty area around and between interface elements, used to group related items, separate unrelated ones and keep a layout uncluttered and easy to read.

148layout

Where items are placed on a screen. Good layout groups related items together, lines them up and leaves space between them, so the screen is easy to scan.

149consistent design

Using the same colours, fonts, alignment and spacing on every part of a dashboard or poster series so it looks unified and is easy to read.

150visual hierarchy

Using size, colour, weight and position so the viewer's eye goes to the most important element first, then follows a clear reading order to the rest.

151text formatting

Using font, size, weight and colour consistently so text is easy to read and shows importance, such as larger bold headings above smaller body text.

152Annotated design review

Checking a mock-up against each UI principle in turn (alignment, balance, contrast, space, text), annotating the improvements needed, then revising the design.

153evaluate a design

To check a design against criteria, like easy to read, easy to use and meets the requirements, using a checklist, user feedback and evidence to show if each one is met.

154Expert review

A testing technique where a knowledgeable specialist examines a solution against established guidelines to find usability and design issues

155criteria table

A table that lists each design option against the same criteria, rates each one, and helps you pick the best design and give reasons for your choice.