QCE Digital Solutions Unit 3 Definitions Worksheet: Real-World Problems and Solution Requirements and Innovative Digital Solutions (Modules 251–337)
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Key terms
Write what each term means, in your own words.
1
Presenting a proposal
2
systems thinking
3
system properties
4
user interface
5
system control
6
Wireframe
7
ALTER TABLE
8
DROP TABLE
9
HAVING
10
WHERE points > (SELECT AVG(points) FROM students)
11
file.close()
12
while True:
13
reliability
14
heuristic review
15
UX critique
16
sustainability
Answer Key
QCE Digital Solutions Unit 3 · Modules 251–337 · Student wording will vary for definitions
1Presenting a proposal — Explain a proposal to its audience in plain language and logical order, using diagrams and justified decisions, then answer questions.
2systems thinking — Seeing a solution as connected parts working together, and using a conceptual model to show those parts and their relationships before building anything.
3system properties — The traits of a system as a whole: its purpose, its components and how they interact, and emergent behaviour that no single part has alone.
4user interface — The part of a system where the user gives inputs and receives outputs. On a conceptual model it sits on the system boundary as the link between the user and the system.
5system control — A mechanism, such as input validation, user feedback or access limits, that keeps a system's behaviour within what is intended.
6Wireframe — A simple, mostly greyscale layout of a screen showing where content and controls sit, using placeholder boxes and no colour, images or final styling.
7ALTER TABLE — An SQL command that changes the structure of an existing table, such as adding, modifying or dropping a column. Existing rows are kept, and a new column is empty (NULL) for them.
8DROP TABLE — Permanently deletes a whole table, its structure and all its records. Unlike DELETE, which only removes rows, it cannot be undone and can fail if other tables reference it.
9HAVING — Filters groups after GROUP BY using a condition on an aggregate, e.g. HAVING COUNT(*) > 2. WHERE filters rows before grouping. HAVING comes after GROUP BY.
10WHERE points > (SELECT AVG(points) FROM students) — A sub-selection is a SELECT inside brackets within another statement. The inner query runs first and its result is used by the outer query, such as in a WHERE condition.
11file.close() — Ends access to an open file so any written data is saved and the file is released. Forgetting it can lose data. A with statement closes the file for you automatically.
12while True: — Starts a menu loop that repeats forever: show options, read a choice, call the matching function with if/elif, reject invalid input, and break when the user picks quit.
13reliability — A solution is reliable when it behaves correctly and consistently every time it is used, even with invalid input or missing files or data. It handles errors without crashing.
14heuristic review — Checking an existing interface against usability rules of thumb (e.g. Nielsen's heuristics), then recording each problem found with its severity and screen evidence.
15UX critique — A review of an existing interface that follows a user's path, judges how well it supports their goals using evidence, and recommends improvements.
16sustainability — How well a solution keeps meeting needs over time without unacceptable environmental, social or economic cost, such as energy use, running and update costs, and social impact.