php insert into mysql

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

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

 // Check connection

 if ($conn->connect_error) {

    die("Connection failed: " . $conn->connect_error);
}


 
$sql = "INSERT INTO MyGuests (firstname, lastname, email)

 VALUES ('John', 'Doe', '[email protected]')";

 
if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();

?>
 

class Database {
	
  	// We make pdo nullable so we can call __destruct and set pdo to null
    protected ?PDO $pdo;
    private string $dsn = 'mysql:dbname=yourDBName;host=127.0.0.1;charset=utf8mb4';
    private string $username = 'mysql_username';
    private string $password = 'password';
    private array $drivers = array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::ATTR_PERSISTENT => false);

    public function __construct()
    {
        try {
            $this->pdo = new PDO($this->dsn, $this->username, $this->password, $this->drivers);
        } catch (\PDOException $e) {
            echo 'Connection Failed: ' . $e->getMessage();
        }
    }
  
  public function insert_category($query, $value): ?bool
    {
    	// This only inserts one field, 
     	// To insert more just spread the $value and use foreach and call_func
		// But I think SQL class should be strict as possible
    	$stmt = $this->pdo->prepare($query); 
        $stmt->bindValue(1, $value, PDO::PARAM_STR);
        $stmt->execute();
        if ($stmt->rowCount() > 0) {
            $stmt = null;
            return true;
        }
        return null;
    }