PHP Interview Questions with Answers Part 5

This is the new fifith episode of PHP Interview preparation Questions with answers. Check out this collection of PHP Interview Questions with simplified Answers.

• How can we extract string 'abc.com ' from a string http://info@abc.com using regular expression of php?
• What is the difference between the functions unlink and unset?
• How come the code works, but doesn’t for two-dimensional array of mine?
• How can we register the variables into a session?
• What is the difference between characters \023 and \x23?
• With a heredoc syntax, do I get variable substitution inside the heredoc contents?
• How can we submit form without a submit button?
• How can we create a database using PHP and mysql?
• How many ways we can retrieve the date in result set of mysql using php?
• Can we use include ("abc.php") two times in a php page "makeit.php"?

How can we extract string 'abc.com ' from a string http://info@abc.com using regular expression of php?

We can use the preg_match() function with "/.*@(.*)$/" as 
the regular expression pattern. For example: 
preg_match("/.*@(.*)$/","http://info@abc.com",$data);
echo $data[1];

What is the difference between the functions unlink and unset?
unlink() is a function for file system handling. It will simply delete the file in context. 

unset() is a function for variable management. It will make a variable undefined.
How come the code works, but doesn’t for two-dimensional array of mine?
Any time you have an array with more than one dimension, complex parsing syntax is required. print "Contents: {$arr[1][2]}" would’ve worked.
How can we register the variables into a session?
session_register($session_var); 

$_SESSION['var'] = 'value';
What is the difference between characters \023 and \x23?
The first one is octal 23, the second is hex 23.
With a heredoc syntax, do I get variable substitution inside the heredoc contents?
Yes.
How can we submit form without a submit button?
We can use a simple JavaScript code linked to an event trigger of any form field. In the JavaScript code, we can call the document.form.submit() function to submit the form. For example: 
How can we create a database using PHP and mysql?
We can create MySQL database with the use of mysql_create_db($databaseName) to create a database.
How many ways we can retrieve the date in result set of mysql using php?
As individual objects so single record or as a set or arrays.
Can we use include ("abc.php") two times in a php page "makeit.php"?
Yes.For Previous Parts click below links

PHP Interview Questions with Answers Part 4
PHP Interview Questions with Answers Part 3
PHP Interview Questions with Answers Part 2
PHP Interview Questions with Answers Part 1