IGCSE Computer Science Paper-1: Specimen Questions with Answers 18 - 19 of 164

Question number: 18

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Short Answer Question▾

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State these five computer terms.

Explanation

Chat rooms: It is a website platform or an online service that helps communities to interact and communicate with each other on a common platform.

Cookies: These are the messages that are passed to our web browser by the web servers whenever we visit the internet sites.

Virus: It is defined as a malicious software program being loaded onto a user’s computer without the user’s knowledge. These viruses can replicate and perform malicious actions.

VoIP: It stands for Voice over Internet Protocol. It enables people to use the Internet as the transmission medium for telephone calls thereby sending voice data in packets using IP

Pharming: it is defined as the malicious practice in which infected and malicious codes are installed on a person’s personal computer or server.

Question number: 19

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List the important difference between the Primary Key, Foreign Key and the Unique Key.

Explanation

Image of The Keys

Image of the Keys

A Primary key is to identify the records or the rows uniquely in a database table. Primary key can never have a null value. A Foreign Key is used to link two or more tables together in a database.

In a table there can be than one Unique key and Unique Key may also consist of null value. Unique Key prevents two records in a table from having identical values.

For Example there are two tables Student and Department both having a common field/column known as ‘ID’. This ‘ID’ acts as the primary key of the Student table and foreign key for the Department Table.

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