QCE Digital Solutions Unit 3 Definitions Worksheet: Interactions Between Users, Data and Digital Systems (Modules 15–119)
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Key terms
Write what each term means, in your own words.
1
control mechanism
2
web application
3
database server
4
server-side code
5
app components
6
analogue vs digital
7
anomaly
8
normalisation
9
Agile development
10
waterfall development
Answer Key
QCE Digital Solutions Unit 3 · Modules 15–119 · Student wording will vary for definitions
1control 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).
2web 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.
3database 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.
4server-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.
5app 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.
6analogue 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.
7anomaly — 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.
8normalisation — 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.
9Agile development — Building a solution in short repeating cycles (sprints), releasing working parts and adapting to user feedback and changing requirements.
10waterfall 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.