PHP interview questions and answers for freshers – Part 1

PHP interview questions, which should help you become a best PHP codder. We hope you find these questions useful. If you are an interviewer, Take the time to read the common interview questions you will most likely be asked.

  • What is PHP?PHP is a server side scripting language commonly used for web applications. PHP has many frameworks and cms for creating websites.Even a non technical person can cretae sites using its CMS.WordPress,osCommerce are the famus CMS of php.It is also an object oriented programming language like java,C-sharp etc.It is very eazy for learning


  • require_once(), require(), include().What is difference between them?require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don’t include the file more times and you will not get the “function re-declared” error.
  • What is the use of ‘print’ in php?This is not actually a real function, It is a language construct. So you can use with out parentheses with its argument list.
    Example print(‘PHP Interview questions’);
    print ‘Job Interview ‘);
  • What is the difference between Session and Cookie?The main difference between sessions and cookies is that sessions are stored on the server, and cookies are stored on the user’s computers in the text file format. Cookies can’t hold multiple variable while session can hold multiple variables..We can set expiry for a cookie,The session only remains active as long as the browser is open.Users do not have access to the data you stored in Session,Since it is stored in the server.Session is mainly used for login/logout purpose while cookies using for user activity tracking


  • How to create a session? How to set a value in session ? How to Remove data from a session?Create session : session_start();
    Set value into session : $_SESSION[‘USER_ID’]=1;
    Remove data from a session : unset($_SESSION[‘USER_ID’];
  • what types of loops exist in php?  for,while,do while and foreach (NB: You should learn its usage)
  • How to create a database connection?
<?php
$servername = "localhost";
$username = "username";
$password = "password";

try {
    $conn = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully"; 
    }
catch(PDOException $e)
    {
    echo "Connection failed: " . $e->getMessage();
    }
?>



<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB"; // Optional

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 
echo "Connected successfully";
?>
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB"; // Optional


// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";
?>
  • Write a program using while loop
<?php 
$x = 1; 

while($x <= 5) {
    echo "The number is: $x <br>";
    $x++;
} 
?>


  • What is the use of explode() function ?Syntax : array explode ( string $delimiter , string $string [, int $limit ] );
    This function breaks a string into an array. Each of the array elements is a substring of string formed by splitting it on boundaries formed by the string delimiter.
  • How to strip whitespace (or other characters) from the beginning and end of a string ?The trim() function removes whitespaces or other predefined characters from both sides of a string.
  • How to redirect a page in php?The following code can be used for it, header(“Location:index.php”);
  • what is the use of isset() in php?This function is used to determine if a variable is set and is not NULL



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Akhil Trivedi