The Internet café must keep records of the users and be able to charge users for the time that they were logged onto the Internet - NSC Information Technology - Question 4 - 2016 - Paper 2

A possible change could be to use a mask edit control that restricts input to a specific time format, showing two combo boxes—one for hours and another for minutes. For example, the format could be represented as 'HH:MM'.

Valid data adheres to the required formats and ranges; for instance, entering a gender must be either 'Male' or 'Female'. In contrast, correct data is associated with the accuracy of the input; if a user incorrectly enters 25 for an hour in the time field, it would be valid according to the input format but incorrect because it exceeds the range of 0-24 hours.

The primary key in the tblComputers should be placed in the tblUsers table as a foreign key. This allows multiple records in tblUsers to link to a single record in tblComputers.

SELECT LogoutTime
FROM tblUsers
WHERE PaymentMethod = 'Debit Card'
ORDER BY LogoutTime;

UPDATE tblUsers
SET PaymentMethod = 'Credit Card'
WHERE UserIDNo = '73110117564076';

SELECT COUNT(UserIDNo) AS CountCashIds
FROM tblUsers
WHERE PaymentMethod = 'Cash';

SELECT *
FROM tblUsers
WHERE (LoginTime > '12:00')
AND (LoginDate = '2016/02/25');

An audit trail records who makes changes to the database and when these changes were made.

1. Using credit or loyalty cards when purchases are made.
2. Collecting data with completion forms for competitions, etc.

This process is referred to as data mining.