PHP MySQL Connect

Connection Methods

🔹 MySQLi Object-Oriented Connection

The object-oriented approach is clean and modern, making your code easier to read and maintain. It's the most popular method among PHP developers today.

<?php
// Connection parameters
$servername = "localhost";
$username = "root";
$password = "";
$database = "mywebsite";

// Create connection object
$conn = new mysqli($servername, $username, $password, $database);

// Check if connection was successful
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

echo "Connected successfully to database!";

// Always close connection when done
$conn->close();
?>
                            

🔹 MySQLi Procedural Connection

The procedural style uses functions instead of objects. It's simpler for beginners but less organized for larger projects.

<?php
// Connection parameters
$servername = "localhost";
$username = "root";
$password = "";
$database = "mywebsite";

// Create connection using function
$conn = mysqli_connect($servername, $username, $password, $database);

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

echo "Connected successfully!";

// Close connection
mysqli_close($conn);
?>
                            

🔹 PDO Connection

PDO (PHP Data Objects) works with multiple database types, not just MySQL. It's great if you might switch databases later.

<?php
$servername = "localhost";
$username = "root";
$password = "";
$database = "mywebsite";

try {
    // Create PDO connection
    $conn = new PDO("mysql:host=$servername;dbname=$database", $username, $password);
    
    // Set error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    
    echo "Connected successfully with PDO!";
} catch(PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}

// Connection closes automatically
?>
                            

🔹 Connection Error Handling

Always check if your connection succeeds and handle errors gracefully to help with debugging:

<?php
$servername = "localhost";
$username = "root";
$password = "wrong_password"; // Intentional error
$database = "mywebsite";

$conn = new mysqli($servername, $username, $password, $database);

// Detailed error checking
if ($conn->connect_error) {
    // Log error for debugging
    error_log("Database connection failed: " . $conn->connect_error);
    
    // Show user-friendly message
    die("Sorry, we're having technical difficulties. Please try again later.");
}

echo "Connection successful!";
$conn->close();
?>
                            

🔹 Reusable Connection File

Create a separate file for database connection that you can include in all your PHP files:

🔸 config.php (Connection File)

<?php
// config.php - Database configuration
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
define('DB_NAME', 'mywebsite');

// Create connection
$conn = new mysqli(DB_SERVER, DB_USERNAME, DB_PASSWORD, DB_NAME);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
?>
                            

🔸 index.php (Using the Connection)

<?php
// Include the connection file
require_once 'config.php';

// Now you can use $conn in this file
echo "Database connected!";

// Your database queries go here...

$conn->close();
?>
                            

🔹 Connection Best Practices