admin_edit.php

<?php
	session_start();
	require_once "./functions/admin_functions.php";
	require_once "./functions/database_functions.php";
	$conn = db_connect();
	require "./template/menu.php";

	if(isset($_GET['bookisbn'])){
		$book_isbn = $_GET['bookisbn'];
	} else {
		echo "Empty query!";
		exit;
	}

	if(!isset($book_isbn)){
		echo "Empty isbn! check again!";
		exit;
	}

	// get book data
	$query = "SELECT * FROM books WHERE book_isbn = '$book_isbn'";
	$result = mysqli_query($conn, $query);
	if(!$result){
		echo "Can't retrieve data " . mysqli_error($conn);
		exit;
	}
	$row = mysqli_fetch_assoc($result);
	$queryForCategory="SELECT * from category";
  	$resultForCategory = mysqli_query($conn, $queryForCategory);
?>
	<form method="post" action="edit_book.php" enctype="multipart/form-data">
		<table class="table">
			<tr>
				<th>ISBN</th>
				<td><input type="text" name="isbn" value="<?php echo $row['book_isbn'];?>" readOnly="true"></td>
			</tr>
			<tr>
				<th>Title</th>
				<td><input type="text" name="title" value="<?php echo $row['book_title'];?>" required></td>
			</tr>
			<tr>
				<th>Author</th>
				<td><input type="text" name="author" value="<?php echo $row['book_author'];?>" required></td>
			</tr>
			<tr>
				<th>Image</th>
				<td><input type="file" name="image"></td>
			</tr>
			<tr>
				<th>Description</th>
				<td><textarea name="descr" cols="40" rows="5"><?php echo $row['book_descr'];?></textarea>
			</tr>
			<tr>
				<th>Price</th>
				<td><input type="text" name="price" value="<?php echo $row['book_price'];?>" required></td>
			</tr>
			<tr>
				<th>Publisher</th>
				<td><input type="text" name="publisher" value="<?php echo getPubName($conn, $row['publisherid']); ?>" required></td>
			</tr>
			<tr>
				<th>Category</th>
				<td>
					<select  name="category">
							<?php $count =0; while($category = mysqli_fetch_assoc($resultForCategory)){ $count=$count+1; ?>
							<option value="<?php echo $category["category_id_pk"]?>" <?php
							if ($row['category_id_fk']==$category["category_id_pk"]) {
								echo 'selected="selected"';
							}
							?>>
							<?php echo $category["name"]?>
							</option>
							<?php }?>
					</select>
				</td>
			</tr>

			<tr>
			<th>Quantity</th>
			<td><input type="text" name="quantity" value="<?php echo $row['quantity']; ?>" ></td>
			</tr>
		</table>
		<input type="submit" name="save_change" value="Change" class="btn btn-primary">
		<input type="reset" value="cancel" class="btn btn-default">
	</form>
	<br/>
	<a href="admin_book.php" class="btn btn-success">Confirm</a>