QCE Digital Solutions Unit 3 — Real-World Problems and Solution Requirements Hangman

The 92 key terms

1Need or opportunity

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

2stakeholder

Any person or group who uses, is affected by, or has an interest in a digital solution, such as users, the client, developers and people affected indirectly.

3Data collection method

A structured technique, such as an interview, survey, or observation, used to gather information about user needs before designing a solution

4decomposition

Splitting a big problem into smaller sub-problems, such as input, process and output. Each part can be solved on its own, then the solutions are combined.

5hierarchy chart

A diagram that splits one main problem into smaller sub-problems in boxes, level by level, until each box is a small task that can be solved on its own.

6Chosen aspect

The one manageable part of a problem your solution will develop, picked by importance and feasibility, linked to stakeholder needs, and justified.

7scope

The boundary of what a solution will and will not include. Features inside the boundary are in scope. Features left out, or saved for later, are out of scope.

8version boundary

A line that sets which features go in the current release and which wait for a later version. It also marks where the solution ends and other systems begin.

9constraint

A limit on how a solution can be made, such as time, cost, skills, devices or software. A constraint is not a feature; it limits what you can build.

10economic constraint

A limit on money that restricts a solution, such as a fixed development budget, software licence fees, or the ongoing costs of hardware, hosting and staff.

11legal constraint

A law or regulation a solution must obey, such as privacy law, copyright and licensing rules, or industry regulations. It limits what the software can do and how it handles data.

12social constraint

A limit on a solution from the needs, values or abilities of the people affected, such as accessibility, cultural expectations and user acceptance.

13Technical constraint

A limit set by technology, such as the hardware, operating system, network or existing software, that a solution must work within.

14limitation

Something the finished solution cannot do, or does only partly, because of constraints and scope decisions. It is stated honestly in a limitation statement, not hidden.

15The solution must

Starts a functional requirement: one thing a digital solution must do. It says what the solution does, not how, and covers one action. Example: The solution must show the score.

16Non-functional requirement

A quality describing how well a system performs, such as speed, security, or reliability, rather than what it does

17measurable non-functional requirement

A quality of a solution, such as speed, security or usability, written with a testable target, like a page loads in under 2 seconds, so you can check whether it is met.

18requirements list

A list that sorts what a solution must do (requirements) from the limits it must work within (constraints), for one problem. Each item should be clear and testable.

19evaluation criterion

A measurable standard used to judge a solution, linked to a requirement and written so it can be answered with evidence, such as a target, a yes/no check or a rating.

20Prescribed criteria

Success criteria set for you by the task, such as an assessment brief or client, that your solution is judged against. Turn each one into a checkable statement.

21self-determined criteria

Success criteria you write yourself from the problem, stakeholder needs and requirements, to add to the prescribed criteria. Make them measurable and avoid repeating prescribed ones.

22IPO 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.

23Ideation technique

A structured method used to generate a wide range of possible solutions to a problem before one is selected for development

24brainstorming

Listing as many ideas as possible quickly, with no early criticism and quantity first, then reviewing the ideas afterwards and grouping them to find the best ones.

25mind map

A diagram with a central topic in the middle and branches and sub-branches that link related ideas, used to generate and organise ideas during design.

26disruptive 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

27role

A job given to one team member with set tasks they are responsible for, so no task is missed and no two people do the same work twice.

28decision matrix

A table that scores each design idea against each criterion, then totals the scores (weighting key criteria) so the best design can be chosen using evidence.

29database table

A database table stores data in columns called fields and rows called records. A single-table database keeps all its data in this one table.

30data 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.

31relational database

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

32PRIMARY 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.

33FOREIGN 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.

34one-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.

35database

A database gives every record the same fields and data types and lets you query large amounts of data; a spreadsheet is a flexible grid.

36TXT file

A plain text file holds unformatted characters, usually one line of text per line ended by a newline. It has no field headings or data types, so everything is read as a string.

37CSV

A text file with one record per line, fields split by a delimiter such as a comma, and an optional header line of field names. Text containing commas goes in quotes.

38<student><name>Mia</name></student>

XML stores data in nested, named elements. Each element has an opening and closing tag, and child elements sit inside a root element. The tags describe the data.

39{"name": "Ava", "year": 12}

JSON stores data as key-value pairs inside curly braces, with lists in square brackets. Objects can nest inside each other, so programs can read it easily. It is a lighter alternative to XML.

40TXT, CSV, XML

Choose a data source by structure: TXT for simple lines, CSV for tables of records, XML for nested self-describing data shared between systems. All three store data between runs.

41one-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).

42record

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).

43grid[row][col]

A 2D array stores data in rows and columns like a table. Use the row index first, then the column index, to reach one element, such as a seat in a seating plan.

44list, 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.

45module

A self-contained part of a program that does one job, so it can be built, tested on its own, reused in other places and changed without breaking the rest of the solution.

46procedure vs function

A procedure carries out a task without returning a value, while a function returns a value to the code that called it, so the result can be stored or used.

47def main(): greet()

A function can call another function inside its body. Big problems get split into small helper functions that each do one job, like boxes in a decomposition.

48naming convention

An agreed pattern for naming variables, functions and controls so code is readable, consistent across a team and easier to maintain and debug.

50readable code

Code that people can quickly understand, using clear names, consistent indentation and spacing, short functions with no repeated code, and helpful comments.

51maintainable code

Code organised so it can be fixed or extended later without breaking other parts, using small functions, classes that hide detail and constants instead of repeated values.

52internal documentation

Comments inside the code, like a header with purpose, author and date, and notes on each function, that help others (or you later) understand and safely change the program.

53# array used because size is fixed

A comment that explains what a variable, array, record or algorithm is for and why it was chosen, rather than just repeating what the code does.

54header comment

A comment at the top of a file that records the program's purpose, author, date and any changes made, so others can understand and maintain the code.

55sequence, branching, iteration

The three building blocks of algorithms: steps in order, decisions (IF) and repeats (loops). Traffic lights, self-serve checkouts, automatic doors and alarm apps all use them.

56end if

A closing keyword in VCAA pseudocode that ends an if block; every nested construct uses end followed by its matching keyword: end if, end while, end for

57Pseudocode

A plain-language, code-like way of planning a solution's logic without following the exact syntax of a real programming language

59input

A VCAA pseudocode keyword that accepts a value from the user and stores it in a named variable. Example: input age stores the user's entered value in the variable age

60print

A VCAA pseudocode keyword that outputs a value, variable or expression as a result. Example: print area displays the current value stored in the variable area

61MOD

The pseudocode operator that returns the remainder after integer division. Example: 10 MOD 3 gives 1 because 10 divided by 3 is 3 remainder 1

63AND

A VCAA pseudocode boolean operator that combines two conditions. The overall result is true only when BOTH conditions are true. Example: x > 0 AND x < 10

64IF-THEN-ELSE

A selection structure that runs one set of instructions if a condition is true, and a different set if it is false

66ELSE IF

A keyword that adds another condition to check if the previous IF or ELSE IF condition was false

67FOR i FROM 1 TO n

A loop that repeats its instructions a fixed number of times, counting the variable i from 1 up to n

68WHILE condition DO

A loop that repeats its instructions for as long as the given condition remains true, checked before each repetition

69REPEAT ... UNTIL condition

A loop that repeats its instructions and checks the condition after each repetition, so the body always runs at least once

70count <- count + 1

A counter. It adds 1 to a variable each time a loop repeats. Set it to 0 before the loop. An accumulator works the same way: total <- total + x adds a value each time.

71scores[1]

Accesses the array element at index 1, using square brackets to specify the position.

72student.name

Accesses the name field of the student record, using a dot to connect the record to its field.

73define

A keyword that starts a function definition, naming the function and listing the parameters it accepts

74return

A keyword that sends a value back from a function to where it was called, ending the function's execution at that point

75addNumbers(3, 4)

Calling a function by writing its name followed by arguments in brackets, running its instructions and possibly producing a value

76addNumbers(a: INTEGER, b: INTEGER): INTEGER

A function header specifying the function's name, its typed parameters, and the data type of its return value

77IPO to pseudocode

Turn each IPO input into an INPUT statement, each process into assignments or IF selection, and each output into a PRINT statement, in that order.

78menu loop

A loop that prints the options, uses a print prompt then input to read a choice, runs the matching action with if / else if, and repeats until the user picks the exit option.

79validation check

A test that an entry is sensible. Types include presence, data type, range, length, format and list. Each one tests a different property of the entry.

80while input is invalid

A loop that reads input, tests it (presence, type, range or length), then shows an error message and asks again until the input passes the check.

81print "Total: " + total

A print statement that joins a label to a value so results are readable. Use headings, labels and one record per line, often inside a loop, to build a report.

82for each record in records

A loop that visits every record in an array once, so you can read, test or change each record's fields, such as counting or totalling the records that match.

83Linear Search

An algorithm that checks each element in an array one at a time, from the start, until the target is found or the end is reached.

84raw data copy

Keep the original data untouched on its own Raw sheet or file, then clean a copy on a Clean sheet, so any mistake can be undone. Version numbers like data_v2 and backups help.

85data cleaning

Finding and fixing mistakes in data, such as typos, spelling variations, duplicate rows, missing values and impossible values, so the data is accurate and ready to use.

86missing value

An empty cell where data should be. Find it with a filter for blanks, then delete the row, fill it from a reliable source or exclude it so AVERAGE and COUNT are not distorted.

87cleaning algorithm

A loop that checks each record with if conditions, trims and standardises text, rejects or fixes bad values, and writes only the good records to a new clean array, leaving the raw data untouched.

88merge algorithm

Loops through one data source, finds the record with the matching key in the other, then combines them or appends unmatched records, avoiding duplicate keys.

89software development brief

A short document that records a problem, need or opportunity so the client and developer agree on what the project is about. It is the written starting point for the project.

90Problem, need or opportunity outline

The part of a brief that clearly and briefly describes the current situation, the need or opportunity, and why a solution is wanted.

91proposed users

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

92feasibility

A judgement of whether a project can realistically be completed given its time, cost, skills and technology (technical, economic and time feasibility).

93Software requirements specification (SRS)

A formal document recording what software must do, so client and developer agree, and used as the basis for design, testing and reference during development.

94SRS content

The parts of an SRS that state the functional and non-functional requirements, the constraints on the solution, and its scope (what is and is not included).

95technical proposal

A structured document that sets out the problem, scope, constraints, requirements, criteria, data design and algorithm outlines in order, so a reader can approve the planned solution.

96Presenting a proposal

Explain a proposal to its audience in plain language and logical order, using diagrams and justified decisions, then answer questions.