PHP Interview Questions and Answers for 2 Year Experienced

Practice here the most popular PHP Job Interview Questions and Answers, which are commonly asked in PHP Interviews.

1. What are the differences between GET and POST methods in PHP?

   Ans: GET and POST are two HTTP methods used to send data to a server. The main differences are:

• GET method sends data through URL parameters, whereas the POST method sends data through the request body.

• The GET method is limited in the amount of data it can send (usually up to 2048 characters), whereas the POST method has no limit.

• The GET method is less secure as the data is visible in the URL, whereas the POST method is more secure as the data is not visible in the URL.

1. What is the difference between require() and include() functions in PHP? Ans: Both functions are used to include a file in a PHP script. The main differences are:

   • require() function will cause a fatal error if the file cannot be found or included, whereas include() function will only give a warning and continue execution.

   • require() function is used for files that are essential for the script to work, whereas include() function is used for files that are optional.

2. What is a session in PHP, and how does it work?

   Ans: A session is a way to store information (variables) on the server to be used across multiple pages of a website. The session information is stored in a temporary file on the server and identified by a unique session ID, which is usually stored in a cookie on the client side. The session ID is sent back to the server with each request, allowing the server to retrieve the session information for that user.

   To start a session in PHP, use the session_start() function at the beginning of each page that needs access to the session data.

3. What is object-oriented programming in PHP, and how is it different from procedural programming?

   Ans: Object-oriented programming (OOP) is a programming paradigm that uses objects (instances of classes) to represent and manipulate data. OOP is different from procedural programming in that it focuses on the objects and their behavior rather than the functions and their execution.

   In PHP, OOP is implemented through classes and objects. Classes define the properties (data) and methods (functions) of the objects, and objects are instances of classes. OOP allows for encapsulation, inheritance, and polymorphism, which can make code more modular and reusable.

4. What is the difference between public, private, and protected visibility in PHP classes?

   Ans: Public, private, and protected are access modifiers that define the visibility of class properties and methods:

   • Public properties and methods can be accessed from anywhere, both inside and outside the class.

   • Private properties and methods can only be accessed from within the class itself.

   • Protected properties and methods can only be accessed from within the class itself and its subclasses (classes that inherit from it).

5. How do you prevent SQL injection attacks in PHP?

   Ans: SQL injection is a common attack where an attacker injects malicious SQL code into a query to manipulate the database. To prevent SQL injection in PHP, you can use:

   • Prepared statements: Prepared statements use placeholders for user input and bind the values separately, preventing the user input from being interpreted as SQL code.

   • Input validation and sanitization: Input validation checks that the user input is of the expected type and format, while sanitization removes any potentially harmful characters from the input.

6. What is the use of the PHP htmlentities() function?

   Ans: The htmlentities() function in PHP is used to convert special characters to their corresponding HTML entities. This is useful when displaying user input on a web page to prevent cross-site scripting (XSS) attacks, where an attacker injects malicious code into a web page.

7. What is the use of the explode() function in PHP?

   Ans: The explode() function is used to split a string into an array. It takes two parameters: the separator string and the string to split.

8. What is the use of the strpos() function in PHP?

   Ans: The strpos() function is used to find the position of the first occurrence of a substring in a string. It takes two parameters: the substring to search for and the string to search in.

9. What is the use of the array_merge() function in PHP?

   Ans: The array_merge() function is used to merge two or more arrays into a single array.

10. What is the use of the session_start() function in PHP?

    Ans: The session_start() function is used to start a new or resume an existing session. It must be called before any output is sent to the browser.

11. What is the difference between include and require in PHP?

    Ans: Both include and require are used to include a file in PHP, but require throws a fatal error if the file is not found, whereas include throws a warning and continues with the execution of the script.

12. What is the difference between GET and POST methods in PHP?

    Ans: GET and POST are HTTP methods used to send data to a server. GET sends data in the URL, whereas POST sends data in the body of the request. GET is less secure than POST because the data is visible in the URL.

13. What is the difference between == and === in PHP?

    Ans: == is a loose comparison operator, whereas === is a strict comparison operator. == checks if the values are equal, whereas === checks if the values and data types are equal.

    Thanks for reading here.