Introduction: Why PHP MySQL Connect Matters

In nearly every dynamic web application, storing and retrieving data is a core requirement. Whether you’re saving user inputs, displaying posts, or managing user accounts—PHP needs to connect to a database, and MySQL is one of the most common choices.

Connecting PHP to MySQL is often the first backend task developers learn. While it's easy to do, it’s crucial to get it right—especially when it comes to security, error handling, and performance.

In this article, we’ll show you how to connect PHP with MySQL using both MySQLi and PDO, step-by-step, with working code snippets and expert tips.

Prerequisites

Before you begin, make sure your environment is ready:

• PHP installed (7.4 or higher recommended)

• MySQL/MariaDB server running

• A local server like XAMPP, MAMP, or WAMP

• A sample database to connect to (e.g., test_db)

Methods to Connect PHP to MySQL

PHP provides two main APIs to connect to MySQL databases:

✅ Method 1: Connect with MySQLi (Object-Oriented)

Step-by-Step

1. Set your database credentials

2. Use new mysqli() to connect

3. Check for connection errors

<?php
// Step 1: Define MySQL server details
$host = "localhost";
$user = "root";
$pass = "";
$dbname = "test_db";

// Step 2: Create connection
$conn = new mysqli($host, $user, $pass, $dbname);

// Step 3: Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "MySQLi Connected successfully!";
?>

✅ Method 2: Connect with PDO (PHP Data Objects)

Step-by-Step

1. Define the DSN (Data Source Name)

2. Use new PDO() to create the connection

3. Set error mode to EXCEPTION

<?php
$host = "localhost";
$dbname = "test_db";
$user = "root";
$pass = "";

try {
    // Create DSN and instantiate PDO
    $pdo = new PDO("mysql:host=$host;dbname=$dbname", $user, $pass);
    
    // Enable exception error mode
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    
    echo "PDO Connected successfully!";
} catch (PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}
?>

Full Working Example

Here’s a full example using MySQLi, complete with connection and a simple query.

<?php
$host = "localhost";
$user = "root";
$pass = "";
$dbname = "test_db";

// Connect using MySQLi
$conn = new mysqli($host, $user, $pass, $dbname);

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

// Create table
$conn->query("CREATE TABLE IF NOT EXISTS contacts (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(50),
    email VARCHAR(50)
)");

// Insert sample data
$conn->query("INSERT INTO contacts (name, email) VALUES ('John Doe', '[email protected]')");

// Read data
$result = $conn->query("SELECT * FROM contacts");

while($row = $result->fetch_assoc()) {
    echo "ID: ".$row['id']." - Name: ".$row['name']." - Email: ".$row['email']."<br>";
}

$conn->close();
?>

⚠️ Tips & Common Pitfalls

✅ Best Practices

• Use PDO for projects that may need to switch databases in the future.

• Always use prepared statements to prevent SQL injection.

• Enable error reporting for debugging during development.

• Store database credentials in a config file for better security.

• Use environment variables for sensitive data in production.

❌ Common Mistakes to Avoid

Summary Table: Connection Syntax

Conclusion: Your Next Steps

Connecting PHP to MySQL is a crucial step in building any data-driven web application. With the power of MySQLi and PDO, you have all the tools to build fast, scalable, and secure apps.

Actionable Takeaways:

• Choose MySQLi for simple projects and PDO for scalability.

• Always handle connection errors gracefully.

• Keep your database credentials safe and separate.

• Practice by creating a small CRUD app to reinforce learning.