Update Db record using PHP and Mysqli

$conn = new mysqli("localhost","root","password","dbname");
if(! $conn ) {
      die('Could not connect to the database ');
}

$userEmail ="russel@example.com";

$updateData = "UPDATE users SET user_email ='$userEmail' WHERE username= 'russel'";
if (mysqli_query($conn, $updateData)) {  
	echo "Record updated successfully";
    } 
else {
	echo "Error updating record: " . mysqli_error($conn);
}