PHP and MySQL form a powerful duo for web development. MySQL is a popular relational database management system, and PHP provides robust tools for interacting with it. This integration allows developers to create dynamic, data-driven websites efficiently.

Connecting to a MySQL Database

To begin working with a MySQL database in PHP, you first need to establish a connection. Here's a basic example:


$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";

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

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";

This code creates a new mysqli object, which represents the connection to your MySQL database. Always check for connection errors to ensure smooth operation.

Executing SQL Queries

Once connected, you can execute SQL queries to interact with your database. Here's an example of a SELECT query:


$sql = "SELECT id, firstname, lastname FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "ID: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "";
    }
} else {
    echo "0 results";
}

This code retrieves all users from the 'users' table and displays their information. The fetch_assoc() method returns each row as an associative array.

Prepared Statements

For improved security and performance, use prepared statements when working with user input:


$stmt = $conn->prepare("INSERT INTO users (firstname, lastname) VALUES (?, ?)");
$stmt->bind_param("ss", $firstname, $lastname);

$firstname = "John";
$lastname = "Doe";
$stmt->execute();

echo "New record created successfully";

$stmt->close();

Prepared statements help prevent SQL injection attacks by separating SQL logic from data. They're especially crucial when dealing with user-supplied data.

Best Practices

Always close your database connection when you're done using it.
Use prepared statements for queries involving user input.
Handle errors gracefully to improve user experience and aid debugging.
Implement proper error logging for production environments.
Use transactions for operations that require multiple queries to maintain data integrity.

Related Concepts

To deepen your understanding of PHP and MySQL integration, explore these related topics:

By mastering these concepts, you'll be well-equipped to build robust, database-driven PHP applications.