Category: Interview Questions

• These are PHP frameworks used for faster development.
• Laravel → most popular, modern syntax.
• CodeIgniter → lightweight, easy to learn.
• Symfony → enterprise-level, modular.

Use Prepared Statements with PDO or mysqli.

$stmt = $conn->prepare("SELECT * FROM users WHERE email = ?");
$stmt->bind_param("s", $email);
$stmt->execute();

1. Encapsulation – Wrapping data & methods in a class.
2. Abstraction – Hiding implementation details.
3. Inheritance – Reusing parent class in child class.
4. Polymorphism – Same method name with different behavior.

• error_reporting()
• try {} catch {} blocks
• set_error_handler()

try {
throw new Exception("Error occurred!");
} catch (Exception $e) {
echo $e->getMessage();
}

$conn = new mysqli("localhost", "root", "", "testdb");
if ($conn->connect_error) {
die("Connection failed!");
}

• Sessions: Store data on the server, unique for each user.
• Cookies: Store data on the client/browser.

• include → gives a warning if file missing, script continues.
• require → gives a fatal error and stops execution.

Predefined global arrays available anywhere in PHP:

• $_GET – data from URL query string
• $_POST – data from forms
• $_SESSION – session variables
• $_COOKIE – cookies
• $_SERVER – server/environment info
• $_FILES – file uploads
• $_REQUEST – combines GET + POST + COOKIE

• == checks for value equality (ignores type).
• === checks for value and type equality.

var_dump(5 == "5");   // true
var_dump(5 === "5");  // false

• String
• Integer
• Float (double)
• Boolean
• Array
• Object
• NULL