Top 10 Questions for PHP Website Developer Interview

1. What is the difference between include() and require() functions?

The main difference between include() and require() function when used in PHP is that require() is used to include a required file and include() is used to include a file in case if file is not found then it shows a warning and continue the execution of the script.

2. What is the purpose of using PDO in PHP?

Benefits of using PDO

• Prepare statements to prevent SQL injection.
• Parameterised queries
• Database Abstraction
• Easier to switch between different databases because of a uniform API.

How PDO works?

• PHP Data Objects (PDO) is a database abstraction layer in PHP which provides a unified API to access different database systems like MySQL, PostgreSQL, Oracle etc.
• It uses Drivers to connect to different databases. PDO provides methods to prepare SQL statements that are executed against the database server.
• It also provides methods to retrieve the results of the query as a result set.

3. Explain the concept of Dependency Injection in PHP?

Dependency Injection (DI) is a technique used to create loosely coupled, maintainable, and extensible applications. In PHP, DI involves defining dependencies of a class or function as parameters, allowing those dependencies to be injected from outside the class or function.

• Promotes code reuse and maintainability.
• Reduces coupling between components.
• Makes it easier to test individual components.
• Supports different implementations of the same interface.

4. Describe the MVC architecture and its benefits in PHP web development?

MVC Architecture

• Model: Represents the data and business logic.
• View: Responsible for presenting the data to the user.
• Controller: Mediates between the model and view, handling user input and managing the flow of the application.

Benefits of MVC

• Separation of concerns, making code more maintainable and reusable.
• Improved code readability and organization.
• Easier testing and debugging.
• Supports collaboration among developers with different skill sets.

5. How do you implement sessions in PHP?

• Starting a session: session_start()
• Storing data in a session: $_SESSION[‘key’] = ‘value’
• Retrieving data from a session: $_SESSION[‘key’]
• Destroying a session: session_destroy()

6. Explain the concept of Object-Oriented Programming (OOP) in PHP?

OOP Concepts

• Classes and Objects
• Encapsulation
• Inheritance
• Polymorphism

Benefits of OOP in PHP

• Code reusability and maintainability.
• Improved code organization and structure.
• Increased flexibility and extensibility.

7. How do you handle and display errors in PHP?

• Using error_reporting() to set the error reporting level.
• Using trigger_error() to manually trigger errors.
• Using die() or exit() to stop the script execution.
• Using custom error handlers to customize error handling.

8. Explain the difference between GET and POST methods in PHP

• GET: Used to send data from the client to the server, typically used for retrieving data.
• POST: Used to send data from the client to the server, typically used for submitting data forms.

9. How do you secure your PHP applications against SQL injection attacks?

• Using prepared statements with PDO.
• Escaping user input using mysql_real_escape_string() or mysqli_real_escape_string().
• Using a database abstraction layer (e.g., Doctrine) that handles escaping and sanitization.

10. Explain the concept of cookies in PHP and how they are used for user authentication?

• Cookies are small pieces of data stored on the client’s device (browser).
• In authentication, cookies are used to store a unique identifier (e.g., session ID) on the client’s device.
• When the user makes subsequent requests, the browser sends the cookie back to the server.
• The server can then verify the cookie to identify the user and provide personalized content or access.

PHP Website Developers are responsible for designing, developing, and maintaining PHP-based websites and applications. They work closely with designers, project managers, and other team members to ensure that websites are visually appealing, functional, and meet the needs of users.

1. Designing and Developing PHP Websites

PHP Website Developers are responsible for designing and developing PHP-based websites and applications. They may work with designers to create website mockups and then use PHP to implement the design and functionality. They may also work with project managers to ensure that websites are completed on time and within budget.

2. Troubleshooting and Debugging PHP Code

PHP Website Developers are responsible for troubleshooting and debugging PHP code. They may need to identify and fix bugs in PHP code, as well as optimize code for performance. They may also need to work with other team members to resolve issues with website functionality.

3. Maintaining PHP Websites

PHP Website Developers are responsible for maintaining PHP-based websites and applications. They may need to update PHP code to fix bugs or add new features, as well as update content on websites. They may also need to work with other team members to ensure that websites are running smoothly and securely.

4. Working with Other Team Members

PHP Website Developers often work with other team members, such as designers, project managers, and other developers. They may need to communicate with designers to ensure that websites are visually appealing, and they may need to work with project managers to ensure that websites are completed on time and within budget. They may also need to work with other developers to resolve issues with website functionality.