PHP Interview Questions
In this article on PHP Interview Questions, I have compiled a list of very basic & fundamental PHP interview questions & answers for web developers. Every PHP web developer should know these basic questions of PHP. So, if you are preparing for any interview in PHP development, you should go through the following list of PHP basic interview questions. There PHP questions are based on very simple PHP concepts like basic introduction to PHP, Sessions & Cookies in PHP, Input / Output in PHP, Error Management in PHP, MySQL database connectivity in PHP, SQL Injection in PHP, Encryption & Decryption in PHP, Sending Emails in PHP, datatypes in PHP & many more. Lets have a look…
1. What is PHP?
PHP is a server side scripting object oriented language commonly used for web applications.
2. What is the use of “echo” in php?
It is used to print a data in the webpage.
Example:
<?php echo ‘Hi’; ?>
The above code print the text in the webpage
3. 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.
4. What’s the difference between include & require?
If the file is not found by require(), it will cause a fatal error & halt the execution of the script. If the file is not found by include(), a warning will be issued, yet execution will continue.
5. What is difference between require_once(), require() & include()?
require() includes & 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 & you will not obtain the “function re-declared” error.
6. Differences between GET & POST methods?
We can send 1024 bytes using GET method yet POST method can transfer large amount of data & POST is the secure method than GET method .
7. How to declare an array in php?
Eg : var $arr = array(‘apple’, ‘grape’, ‘lemon’);
8. What is the use of ‘print’ in php?
This is not actually a real function, It is a language construct. So you can use without parentheses with its argument list.
Example:
print(‘PHP Interview Questions’);
print ‘PHP Interview Questions’;
9. What is use of in_array() function in php?
in_array used to checks if a value exists in an array
10. What is use of count() function in php?
count() is used to count all elements in an array, or something in an object
11. What is the difference between Session & Cookie?
The main difference between sessions & cookies is that sessions are stored on the server, & cookies are stored on the user’s computers in the text file format. Cookies can not hold multiple variables, yet Session can hold multiple variables. We can set expiry for a cookie while the session only remains active as long as the browser is open. Users do not have access to the data you stored in Session because it is stored in the server. Session is mainly used for login/logout purpose while cookies using for user activity tracking
12. How to set cookies in PHP?
Setcookie(“sample”, “ram”, time()+3600);
13. How to retrieve a Cookie Value?
eg : echo $_COOKIE["user"];
14. 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'];
15. What types of loops exist in php?
for,while,do while & foreach
16. How to create a mysql connection?
mysql_connect(servername,username,password);
17. How to select a database?
mysql_select_db($db_name);
18. 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'];
19. 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/>”;
}
20. How we can retrieve the data in the result set of MySQL using PHP?
1. mysql_fetch_row
2. mysql_fetch_array
3. mysql_fetch_object
4. mysql_fetch_assoc
