PHP Questions

Q:

What is PHP's mysqli Extension?

Answer

The mysqli extension , or as it is sometimes known, the MYSQL improved extension ,was developed to take advantage of new features found in MYSQL systems versions 4.1.3 and later.

The mysqli extension has a number of benfits,the key enhancements over the mysql extension being:
=> Object-oriented interface
=> Support for prepared statements
=> Support for multiple statements
=> Support for transactions
=> Enhanced debugging capabilities
=> Embedded server support

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Subject: PHP - Technology

0 2029
Q:

So if md5( ) generates the most secure hash, why would you ever use the less secure crc32( ) and sha1( )?

Answer Crypto usage in PHP is simple, but that doesn’t mean it’s free. First off, depending on the data that you’re encrypting, you might have reasons to store a 32-bit value in the database instead of the 160-bit value to save on space. Second, the more secure the crypto is, the longer is the computation time to deliver the hash value. A high volume site might be significantly slowed down, if frequent md5() generation is required.
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Subject: PHP - Technology

0 2027
Q:

For printing out strings, there are echo, print and printf. Explain the differences.

Answer - echo is the most primitive of them, and just outputs the contents following the construct to the screen. print is also a construct (so parentheses are optional when calling it), but it returns TRUE on successful output and FALSE if it was unable to print out the string. However, you can pass multiple parameters to echo, like:

and it will output the string "Welcome to TechInterviews!" print does not take multiple parameters. It is also generally argued that echo is faster, but usually the speed advantage is negligible, and might not be there for future versions of PHP. printf is a function, not a construct, and allows such advantages as formatted output, but it’s the slowest way to print out data out of echo, print and printf.
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Subject: PHP - Technology

0 1949
Q:

How can we get the browser properties using PHP?

Answer

By using
$_SERVER['HTTP_USER_AGENT']
variable.

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Subject: PHP - Technology

0 1947
Q:

What’s the special meaning of __sleep and __wakeup?

Answer __sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them.
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Subject: PHP - Technology

0 1930
Q:

What is the difference between characters 23 and x23?

Answer The first one is octal 23, the second is hex 23
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Subject: PHP - Technology

0 1929
Q:

What is the difference between _construct() and _destruct() methods in php?

Answer

These two methods are bulid-in methods  in php. with  construct() we can overwride the parent class method. The inverse of the __construct() PHP capacity while making another class, is the __destruct() technique. The __destruct() technique will consequently keep running, after you've completed with the PHP class.

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Subject: PHP - Technology
Job Role: Software Architect

1 1878
Q:

How do you destroy a particular or all Sessions?

Answer

<?php
session_start();
// store session data
$_SESSION['views']=1;
unset($_SESSION['views']); // If you wish to delete some session data, you can use the unset()
session_destroy(); // You can also completely destroy the session by calling the session_destroy() function. session_destroy() will reset your session and you will lose all your stored session data.
?>

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