Frequently Asked
Questions

Both echo and print are used to output data in PHP, but echo is faster than print. echo can take multiple parameters and has no return value, while print can only take one argument and returns 1, making it suitable for use in expressions.

PHP supports various data types, including integers, floats, strings, booleans, arrays, objects, and resources. It also has a special type called NULL indicating a variable with no value.

Both include and require are used to include and evaluate external files in a PHP script. The difference is that if an error occurs while including a file with require, the script will terminate, whereas include will only produce a warning.

The mysqli extension provides enhanced features for working with MySQL databases in PHP. It supports improved security, object-oriented syntax, and prepared statements, making it a recommended choice for database interactions.

• Inheritance: It allows a class to inherit properties and methods from another class.
• Encapsulation: It involves bundling the data (attributes) and the methods that operate on the data into a single unit or class.
• Polymorphism: It allows objects of different classes to be treated as objects of a common base class, providing a way to use a single interface for different types of objects.

A constructor is a special method in a class that is automatically called when an object is created. It is used to initialize object properties. A destructor, on the other hand, is used to perform cleanup tasks before an object is destroyed, and it is called automatically when an object is no longer in use.

Sessions in PHP are used to persist data across multiple pages for a single user. Session data is stored on the server, and a session ID is used to track the user. Sessions can be managed using the session_start() function and session variables.

• GET: Data is appended to the URL, and it is visible in the browser's address bar. It has a limitation on the amount of data that can be sent.
• POST: Data is sent in the body of the HTTP request, and it is not visible in the URL. It is suitable for sensitive or large amounts of data.

To prevent SQL injection, use prepared statements and parameterized queries with either MySQLi or PDO (PHP Data Objects). These methods separate SQL code from user input, preventing malicious SQL code execution.

XSS occurs when user input is improperly validated and then displayed on a web page, allowing the execution of malicious scripts. To prevent XSS, input validation, output escaping, and the use of secure coding practices are essential.

Composer is a dependency manager for PHP that simplifies the process of managing libraries and dependencies in a project. It helps autoload classes, manage project dependencies, and ensures consistency across different environments.

Namespaces are a way to organize code by encapsulating classes, functions, and constants under a specific name. They prevent naming conflicts and provide a structured way to group related code.