<?php

include_once 'database/connect.php';
include_once 'functions/general.php';
if (isset($_GET['id'])) {
    $id = $_GET['id'];
    $results = retrieveTextbook($_GET['id'], $dbconn);
    if (isActiveUser($results['UserId'], $dbconn)) {
        $currentUser = true;
    } else {
        $currentUser = false;
    }
}
<?php

include_once 'database/connect.php';
include_once 'functions/general.php';
session_start();
if (isset($_GET['ref'])) {
    $ref = $_GET['ref'];
    $id = bookRefToId($ref, $dbconn);
    $results = retrieveTextbook($id, $dbconn);
    $user = retrieveUser($results['UserId'], $dbconn);
    $categories = retrieveCategories($dbconn);
    $conditions = retrieveConditions($dbconn);
    if (isActiveUser($user['UserId'], $dbconn)) {
        $currentUser = true;
    } else {
        $currentUser = false;
    }
}
<?php

include_once 'database/connect.php';
include_once 'functions/general.php';
include_once 'validation.php';
$ref = $_GET['ref'];
$id = bookRefToId($ref, $dbconn);
$book = retrieveTextbook($id, $dbconn);
if (isActiveUser($book['UserId'])) {
    try {
        $sql = $dbconn->prepare("DELETE FROM `textbooks` WHERE `BookId` = :id");
        $sql->execute();
        $sql->bindParam(':id', $id);
        $imagesql = $dbconn->prepare("DELETE FROM `textbook-images` WHERE `BookId` = :id");
        $imagesql->bindParam(':id', $id);
        $imagesql->execute();
        if ($sql->execute() || $imagesql->execute()) {
            header("location: ../myuploads.php");
        } else {
            echo 'Unable to delete Textbook  !';
        }
    } catch (PDOException $e) {
        errorHandle($e);
    }
}