mysqli multi query — PHP Использование неопределенных констант bigdata

Код работает правильно с ошибкой:

Примечание: использование неопределенных констант bigdata — предполагается, что bigdata
C: \ xampp \ htdocs \ dynamic_menu \ index.php в строке 4

Код следующим образом:

    //Set the database connection
($GLOBALS["___mysqli_ston"] = mysqli_connect('localhost', 'root', 'chethan'));
((bool)mysqli_query($GLOBALS["___mysqli_ston"], "USE " . 'bigdata'));
//select all rows from the main_menu table
$result = mysqli_query($GLOBALS["___mysqli_ston"], "select id,title,parentid,link from main_menu");

//create a multidimensional array to hold a list of menu and parent menu
$menu = array(
'menus' => array(),
'parent_menus' => array()
);

//build the array lists with data from the menu table
while ($row = mysqli_fetch_assoc($result)) {
//creates entry into menus array with current menu id ie. $menus['menus'][1]
$menu['menus'][$row['id']] = $row;
//creates entry into parent_menus array. parent_menus array contains a list of all menus with children
$menu['parent_menus'][$row['parentid']][] = $row['id'];
}

// Create the main function to build milti-level menu. It is a recursive function.
function buildMenu($parent, $menu) {
$html = "";
if (isset($menu['parent_menus'][$parent])) {
$html .= "<ul>";
foreach ($menu['parent_menus'][$parent] as $menu_id) {
if (!isset($menu['parent_menus'][$menu_id])) {
$html .= "<li><a href='" . $menu['menus'][$menu_id]['link'] . "'>" . $menu['menus'][$menu_id]['title'] . "</a></li>";
}
if (isset($menu['parent_menus'][$menu_id])) {
$html .= "<li><a href='" . $menu['menus'][$menu_id]['link'] . "'>" . $menu['menus'][$menu_id]['title'] . "</a>";
$html .= buildMenu($menu_id, $menu);
$html .= "</li>";
}
}
$html .= "</ul>";
}
return $html;
}