$room->Start = $from;
    $room->End = $to;
    if ($room->Updateroom()) {
        echo "success";
    }
} else {
    if (empty($Discount) || $Discount == 0) {
        echo "Insert a value on Discount Amount to add Promo";
    } else {
        $Start = \DateTime::createFromFormat('d/m/Y', $from)->format('Y-m-d');
        $End = \DateTime::createFromFormat('d/m/Y', $to)->format('Y-m-d');
        $sql = "select * from tblrooms where Room_ID='{$hideID}'";
        $result = mysqli_query($conn, $sql);
        $row = mysqli_fetch_assoc($result);
        $HiddenID = $row['Room_ID'];
        $room->HiddenID = $HiddenID;
        $room->RoomID = $Roomid;
        $room->CategoryID = (string) Category::GetCategoryID($Categoryname);
        $room->Discount = $Discount;
        $room->Rate = $Rate;
        $room->Descript = $Descript;
        $room->Status = $Status;
        $room->Noadult = $Adult;
        $room->Nochild = $Child;
        $room->Start = $Start;
        $room->End = $End;
        if ($room->Updateroom()) {
            echo "success";
        }
    }
}
<?php 
include '../pdoconnection.php';
include '../Class/Room.php';
include '../Class/Categories.php';
if (isset($_GET['roomid'])) {
    $roomid = $_GET['roomid'];
    $sql = "SELECT * FROM tblrooms WHERE Room_ID='{$roomid}'";
    $result = $conn->query($sql);
    $row = $result->fetch(PDO::FETCH_ASSOC);
    if (!Room::RoomEmpty($roomid)) {
        echo "This Room has still promo rooms. please delete all promo rooms before this";
    } else {
        $Image = "photos/";
        $imageFileType = pathinfo($Image, PATHINFO_EXTENSION);
        $room = new Room();
        $room->RoomID = $roomid;
        $room->CategoryID = (string) Category::GetCategoryID($row['Category_ID']);
        $room->Rate = $row['Rate'];
        $room->Descript = $row['Description'];
        $room->Status = $row['Status'];
        $room->Noadult = $row['No_adult'];
        $room->Nochild = $row['No_child'];
        $room->Image = $row['Image'];
        if ($room->Deleteroom()) {
            unlink($imageFileType . $row['Image']);
            header("Location: manageroom.php");
        }
    }
}
 public static function CAtegoryEmpty($categoryname)
 {
     $isEmpty = false;
     $sql = "select COUNT(Category_ID) from tblrooms where Category_ID='" . Category::GetCategoryID($categoryname) . "' ";
     include '../../connection.php';
     $query = mysqli_query($conn, $sql);
     $row = mysqli_fetch_array($query);
     $num = $row['COUNT(Category_ID)'];
     if ($num > 0) {
         $isEmpty = false;
     } else {
         $isEmpty = true;
     }
     mysqli_close($conn);
     return $isEmpty;
 }
<?php

include '../../connection.php';
include '../class/categories.php';
include '../class/room.php';
if (isset($_GET['categoryname'])) {
    $categoryname = $_GET['categoryname'];
    if (!Category::CAtegoryEmpty($categoryname)) {
        echo '<script type="text/javascript">';
        echo 'alert("This Category has still rooms. please delete all rooms before removing the Category");';
        echo 'window.location.href = "manageroom.php";';
        echo '</script>';
    } else {
        $Category = new Category(Category::GetCategoryID($categoryname), $categoryname);
        if ($Category->DeleteCategory()) {
            echo "success";
            header('Location: manageroom.php');
        }
    }
}