How validation and verification keep data accurate, the checks to apply (range, reasonableness, data type, consistency, presence, format, length, double entry, proofreading), and how sequential, serial, direct and random access suit different applications.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
A date of birth in the year 2090 or a mark of 150 out of 100 should never reach a database. Validation stops it; verification makes sure what was typed matches the source.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Try different values through a validation check, and compare serial, sequential and random access.
Copy these into your notebook in your own words — that is how they stick.
Computer checks that data is reasonable and correctly formed.
Checks that the entry matches the source.
Range, reasonableness, data type, consistency, presence, format, length.
Double entry, proofreading.
Typographical and transposition.
In key order / in order of arrival; read from the start; batch jobs.
Jump to a record using its key; real-time systems.
Archiving, payroll → sequential/serial; real-time → direct.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Information Technology Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
A clinic stores patient records on a computer. At registration the clerk enters the patient’s ID number (8 digits), date of birth, sex and phone number.
(a) (a) Distinguish between validation and verification. [4]
(b) (b) State the validation check that would be most appropriate for each: (i) the ID number has exactly 8 digits, (ii) the date of birth is not left blank, (iii) the date of birth is not in the future. [3]
(c) (c) The clerk types 0725164 instead of 0725146 for an ID. Name this type of error and one method to detect it. [3]
(d) (d) The clinic keeps old patient files for 20 years. Suggest a suitable file organisation and storage and explain your choice. [3]
(e) (e) State why direct access is needed when a nurse looks up one patient during a visit. [2]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.