Old values not appearing when editing PHP MySQL - php

Question

So, I am doing a library system. A librarian can view all the books, and may choose to edit a book and it's details. However, when I click edit, the values do not show up in the input field.
This is my edit portion of the code. I am getting an error:
count(): Parameter must be an array or an object that implements
Countable on line 7
which is if (count($record) == 1 ) {:
<?php
if (isset($_GET['edit'])) {
$id = $_GET['edit'];
$update = true;
$record = mysqli_query($db, "SELECT * FROM bookinfo WHERE BookNo='$BookNo'");
if (count($record) == 1 ) {
$n = mysqli_fetch_array($record);
$BookNo = $n['BookNo'];
$ISBN = $n['ISBN'];
$title = $n['title'];
$author = $n['author'];
$publisher = $n['publisher'];
$status = $n['status'];
$cost = $n['cost'];
}
}
?>
This is my displaying of the data for the librarian, along with the edit button:
<?php while ($row = mysqli_fetch_array($results)) { ?>
<tr>
<td><?php echo $row['BookNo']; ?></td>
<td><?php echo $row['ISBN']; ?></td>
<td><?php echo $row['title']; ?></td>
<td><?php echo $row['author']; ?></td>
<td><?php echo $row['publisher']; ?></td>
<td><?php echo $row['status']; ?></td>
<td><?php echo $row['cost']; ?></td>
<td>
<a href="viewBook.php?edit=<?php echo $row['BookNo']; ?>" class="edit_btn" >Edit</a>
</td>
Followed by, the fields in which the librarian can edit the details.
<?php
if (isset($_GET['edit'])) { ?>
<form method="post" action = "viewBook.php">
<input type="hidden" name="BookNo" value="<?php echo $BookNo; ?>">
<input type="text" name="ISBN" value="<?php echo $ISBN; ?>">
<input type="text" name="title" value="<?php echo $title; ?>">
<input type="text" name="author" value="<?php echo $author; ?>">
<input type="text" name="publisher" value="<?php echo $publisher; ?>">
<input type="text" name="status" value="<?php echo $status; ?>">
<input type="text" name="cost" value="<?php echo $cost; ?>">
<?php if ($update == true): ?>
<button class="btn" type="submit" name="update" style="background: #556B2F;" >update</button>
<?php else: ?>
<button class="btn" type="submit" name="save" >Save</button>
<?php endif ?>
<?php } ?>
</form>
When I click the edit button, I get the error stated above, as well as the text fields not having the details already written inside.

Answer 1

count() function only works with arrays and other countable fields
use the mysqli_num_rows
<?php
if (isset($_GET['edit'])) {
$id = $_GET['edit'];
$update = true;
$record = mysqli_query($db, "SELECT * FROM bookinfo WHERE BookNo='$BookNo'");
if (mysqli_num_rows($record) == 1 ) {
$n = mysqli_fetch_array($record);
$BookNo = $n['BookNo'];
$ISBN = $n['ISBN'];
$title = $n['title'];
$author = $n['author'];
$publisher = $n['publisher'];
$status = $n['status'];
$cost = $n['cost'];
}
}
?>
this mysqli_num_rows can give you result of the count of amount of data from sql query
I think this will work for you.

Answer 2

use mysqli_fetch_assoc()
So, I am doing a library system. A librarian can view all the books, and may choose to edit a book and it's details. However, when I click edit, the values do not show up in the input field.
This is my edit portion of the code. I am getting an error:
count(): Parameter must be an array or an object that implements Countable on line 7
which is if (count($record) == 1 ) {:
<?php
if (isset($_GET['edit'])) {
$id = $_GET['edit'];
$update = true;
$record = mysqli_query($db, "SELECT * FROM bookinfo WHERE BookNo='$BookNo'");
if (count($record) == 1 ) {
$n = mysqli_fetch_assoc($record);
$BookNo = $n['BookNo'];
$ISBN = $n['ISBN'];
$title = $n['title'];
$author = $n['author'];
$publisher = $n['publisher'];
$status = $n['status'];
$cost = $n['cost'];
}
}
?>