How can differences in PHP versions and environments impact the functionality of database-related code in PHP scripts?

Differences in PHP versions and environments can impact the functionality of database-related code in PHP scripts due to changes in syntax, deprecated functions, or differences in default configurations. To ensure compatibility, it's important to use standardized database functions and libraries, and to test the code across different PHP versions and environments.

// Example of using PDO (PHP Data Objects) to connect to a database in a way that is compatible with different PHP versions and environments

// Database credentials
$host = 'localhost';
$dbname = 'my_database';
$username = 'root';
$password = '';

// Create a PDO instance
try {
    $pdo = new PDO("mysql:host=$host;dbname=$dbname", $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
    die("Error connecting to database: " . $e->getMessage());
}

// Example query
$stmt = $pdo->prepare("SELECT * FROM users");
$stmt->execute();
$users = $stmt->fetchAll(PDO::FETCH_ASSOC);

// Display results
foreach ($users as $user) {
    echo $user['name'] . "<br>";
}