public function buyStock($stock, $quantity)
{
$portfolio = new table_Portfolio();
$where = "CAUS_NM_ID={$_SESSION['userid']} and COAT_TX_ID='{$stock}'";
$port = $portfolio->fetchRow($where);
if ($port != null) {
$qty = $port->CART_NM_Quantidade;
$totalQty = $qty + $quantity;
$data = array('CART_NM_Quantidade' => $totalQty);
$portfolio->update($data, $where);
} else {
$data = array('CAUS_NM_ID' => $_SESSION['userid'], 'COAT_TX_ID' => $stock, 'CART_NM_Quantidade' => $quantity);
$portfolio->insert($data);
}
}
