COMMON INTERVIEW QUESTIONS ASKED IN TCS (TATA CONSULTANCY SERVICES) BASED ON PHP WEB DEVELOPMENT CONCEPTS ALONG WITH THE ANSWERS(PART 1)

Q1. Explain the difference between GET and POST requests?

Ans: The difference between GET and POST requests or rather you can say the difference between GET() method and POST() method are as follows :-

GET request (GET() Method) => GET request is not at all a secure method as the GET request is an unsecure method. GET request can sent the query string.

POST request (POST() Method) => POST request is the secure method. POST request cannot sent the query string.

Q2. What is a session in PHP? How does session work? 

Ans: Session in PHP is known as a globalcarrier of data which trace the user's activity on website.

                            Session work like it sends user information to the server.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     Session is more secure. Session doesnot haveany limit. For Example: Login, Logout,Multipart Form.

Q3. What is the difference between sessions and cookies? 

Ans: The difference between session andcookies are as follows:

Cookies - Cookies is a small file sent by the server to the client machine through web browser which trace how long ago the user has visited the website. Cookies is used to sent the user information to the client machine. Cookies can sent data of 0-2048 bytes. Cookies is less secure. Cookies is known as global carrier of data. Real Life Example : Remember Me.

Session - Session is also known as global carrier of data which trace the user's activity on website. Session is used to sent the user's information on server. Session is more secure. Session doesn't have any limit. For example : Login, Logout, Multipart Form.

Q4. How does PHP handle user input from forms? 

Ans: PHP handle user input from forms by displaying submitted data. Which means that once the form is submitted, PHP process and display user inputs by using $_GET or $_POST superglobal variables, depends on the form method. For example:

<form action="formaction.php"></form> 

<form action="editaction.php"></form> 

Q5. Explain the concept of SQL Injection and how to prevent it.

Ans: SQL Injection is basically known as malfunction like on web application database the attackers or spammers inject sql query to hack or for malfunction. For example:

$sql="SELECT * FROM `users` WHERE `username`='$username';

which means $sql="SELECT * FROM `users` WHERE `username`='' OR '1'='1' which states that 1=1 which both are true, which returns all users to expose sensitive data.

To prevent SQL Injection, I need to use prepare statement which helps the users to protect from hackers or spammers to expose the user's sensitive data by attacking and by providing SQL Injection. For example:

$sql="SELECT * FROM `users` WHERE `username`='$username';

$query=$conn->prepare($sql).