function addVisiting()
{
if (!isset($_SESSION['isOldVisiting'])) {
$model = new CI_Model();
$today = date('Y-m-d', time() + 7 * 3600);
if ($model->getRowByColumn('thongke', 'ngaythang', $today)) {
$currentVisitingNumber = $model->getRowByColumn('thongke', 'ngaythang', $today)->soluong;
$currentVisitingNumber += 1;
$input = array('ngaythang' => $today, 'soluong' => $currentVisitingNumber);
$model->updateRowByColumn('thongke', 'ngaythang', $today, $input);
} else {
$input = array('ngaythang' => $today, 'soluong' => 1);
$model->insertNewRow('thongke', $input);
}
$_SESSION['isOldVisiting'] = 'true';
}
}