PHP Interview Questions and Answers

Oct 11, 2013, by admin

Hi all today we are going to see in the post is PHP Interview Questions and answers asked during the interview for the job PHP Developer hope the post will useful for the freshers

• 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

• What is the use of “echo” in php?

It is used to print a data in the webpage, Example: <?php echo ‘Car insurance’; ?> , The following code print the text in the webpage

• How to include a file to a php page?

We can include a file using “include() ” or “require()” function with file path as its parameter.

• What’s the difference between include and require?

If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

• 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.

• Differences between GET and POST methods ?

We can send 1024 bytes using GET method but POST method can transfer large amount of data and POST is the secure method than GET method .

• How to declare an array in php?

Eg : var $arr = array(‘apple’, ‘grape’, ‘lemon’);

• 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 use of in_array() function in php ?

in_array used to checks if a value exists in an array

• What is use of count() function in php ?

count() is used to count all elements in an array, or something in an object

• What’s the difference between include and require?

It’s how they handle failures. If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

• 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 not hold multiple variables,But 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 set cookies in PHP?

Setcookie(“sample”, “ram”, time()+3600);

• How to Retrieve a Cookie Value?

eg : echo $_COOKIE[“user”];

• 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 mysql connection?

mysql_connect(servername,username,password);

• How to select a database?

mysql_select_db($db_name);

• How to execute an sql query? How to fetch its result ?

$my_qry = mysql_query(“SELECT * FROM `users` WHERE `u_id`=’1′; “);
$result = mysql_fetch_array($my_qry);
echo $result[‘First_name’];

• Write a program using while loop

$my_qry = mysql_query(“SELECT * FROM `users` WHERE `u_id`=’1′; “);
while($result = mysql_fetch_array($my_qry))
{
echo $result[‘First_name’.].”<br/>”;
}

• How we can retrieve the data in the result set of MySQL using PHP?
• What is the use of explode() function ?

• 1. mysql_fetch_row
• 2. mysql_fetch_array
• 3. mysql_fetch_object
• 4. mysql_fetch_assoc

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.

• What is the difference between explode() and split() functions?

Split function splits string into array by regular expression. Explode splits a string into array by string.

• What is the use of mysql_real_escape_string() function?

It is used to escapes special characters in a string for use in an SQL statement

• Write down the code for save an uploaded file in php.

if ($_FILES[“file”][“error”] == 0)
{
move_uploaded_file($_FILES[“file”][“tmp_name”],
“upload/” . $_FILES[“file”][“name”]);
echo “Stored in: ” . “upload/” . $_FILES[“file”][“name”];
}