3i Infotech Papers: Sample Questions 280 - 281 of 1245

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Question number: 280

» Database » MySQL

Essay Question▾

Describe in Detail

What are the wildcards used for pattern matching?

Explanation

Undrstanding of wildcards

Undrstanding of Wildcards

Undrstanding of wildcards

  • Wildcard character is used to substitute other character in a string.

  • Used with SQL LIKE operator.

  • LIKE operator is used in a WHERE clause to search a specified pattern in a column.

Two wildcards used in LIKE operator:

  • %- Represent zero, one, or multiple characters.

  • _ - Represent a single character.

Syntax of %

SELECT FROM table_name

WHERE column LIKE ‘XXXX%’ or ‘%XXXX%’

Syntax of _

SELECT FROM table_name

WHERE column LIKE ‘XXXX_’ or ‘_XXXX’ or ‘_XXXX_’

Question number: 281

» Basic CS » Operating System

Essay Question▾

Describe in Detail

What is a trap and trapdoor?

Explanation

Image shows the TRAP

Image Shows the TRAP

Image shows the TRAP

Image shows the Trap door

Image Shows the Trap Door

Image shows the Trap door

Trap:

  • Trap is a software generate interrupt.

  • Occurs when some exceptional conditions occurs- like divide by 0, process accessing memory outside address space.

  • There are two kinds of traps- hard traps are called interrupts, and software related traps are called exceptions.

Trap door:

  • Trap door in modern terminology has nothing to do with traps.

  • It is a secret undocumented entry point into a program granting access without normal authentication.

  • Generally maliciously- hidden software mechanism allowing the attacker to circumvent the security.

  • Malicious code can then allow unauthorized access to a computer system or network accepting remote commands.

  • Code listens for commands on transmission control protocol or user datagram protocol.