PHP Interview Questions

PHP is a server-side scripting language specifically designed for web development and can be embedded directly into HTML.

It is widely used for building dynamic websites, content management systems (CMS), and backend services.

PHP scripts are executed on the server, generating HTML output that is sent to the client browser.

Popular platforms like WordPress, Drupal, and Laravel are built using PHP, highlighting its versatility and long-standing presence in the web development world.

Sessions and cookies are mechanisms used in PHP to store user-specific information across HTTP requests.

Cookies are stored on the client's browser and can be accessed using the $_COOKIE superglobal array.

Sessions, on the other hand, are stored on the server and associated with a unique session ID sent to the client as a cookie.

In PHP, sessions are started using session_start() and data is stored in the $_SESSION array.

Both cookies and sessions play a vital role in user authentication, personalization, and tracking user behavior across visits.

PHP provides several ways to interact with MySQL databases, including the older mysql_* functions (now deprecated), mysqli_* functions, and PDO (PHP Data Objects).

Using mysqli, you can establish a connection like this: $conn = mysqli_connect('localhost', 'username', 'password', 'database');

Queries can be executed using mysqli_query(), and results can be fetched using functions like mysqli_fetch_assoc().

For better security and portability, it's recommended to use prepared statements with PDO or MySQLi to prevent SQL injection attacks.