PHP variables keep resetting - php

Question

I am trying to use PHP to update an SQL table using HTML forms.
I want the user to be able to search for a VCR name and display it details in a while loop and then an update form will appear for the user to change its details in the database.
However every time i press the update button on the update form, the variables that hold the new details empty and become undefined.
<?php require('connect.php'); ?>
<?php require('headerPrivate.php'); ?>
<?php require('session.php');?>
<?php
//SEARCH PHP CODE
//THIS WORKS FINE AND ALL THE DETAILS APPEAR
if(isset($_POST["search"]))
{
//CREATE VARIABLES
$username=$_SESSION['username'];
echo "username: ".$username;
echo '<br>';
$vcrName=$_POST['name'];
echo "VCR Name: ".$vcrName;
echo '<br>';
echo '<br>';
//SELECT * FROM PRODUCT
$sql="SELECT *
FROM product
INNER JOIN user
ON product.owner_ID=user.user_ID
WHERE username='$username' AND name='$vcrName'";
echo "SQL SELECT 1: ".$sql;
echo '<br>';
echo '<br>';
//$vcrName=$_POST['name'];
$result = mysqli_query($con,$sql);
echo '<div class="row">';
echo '<div class="col-xs-6 col-md-4">';
while ($row_all = mysqli_fetch_assoc($result))
{
echo '<form method="post">';
echo "<u>Title: ".$row_all["name"].'</u>';
echo '<br>';
echo '<small>';
echo " Price: ".$row_all["price"];
echo '</small>';
echo '<br>';
echo "<p><u>Short Description:</u> ".$row_all["short_descripton"]."</p>";
echo '<br>';
echo "<p><u>Long Description:</u> ".$row_all["long_description"]."</p>";
echo '<br>';
echo '<hr>';
echo '</form>';
echo '<div>';
}
echo '</div>';
}
?>
<content>
<!--SEARCH FOR VCR NAME-->
<form class="form" method="post">
<label for="name" class="sr-only">VCR Name</label>
<input type="text" name="name" class="form-control" placeholder="VCR Name" required="" autofocus="" autocomplete="off">
<button name="search" type="search" class="btn btn-success btn-block">Search</button>
</form>
<?php
//This is where i run into issues. The old name in the variable $vcrName is empty and i need it for the update SQL statement.
//UPDATE PHP
if(isset($_POST["alter"]))
{
//CREATE A SESSION VARIABLE FOR THE CUSTOMER ID
$customer_ID=$_SESSION['customer_ID'];
echo "Customer ID: ".$customer_ID;
echo '<br>';
//CREATE VARIABLES
$changeTitle=$_POST["titleChange"];
$changesDescChange=$_POST["sDescChange"];
$changelDescChange=$_POST["lDescChange"];
$changepriceChange=$_POST["priceChange"];
$vcrName=$_POST['name'];
//UPDATE SQL
$sql_update="UPDATE product
SET
name='$changeTitle',
short_descripton='$changesDescChange',
long_description='$changelDescChange',
price='$changepriceChange'
WHERE
owner_ID='$customer_ID' AND name='$vcrName'";
echo "SQL Update 0: ".$sql_update;
echo '<br>';
echo '<br>';
echo "Updated Name: ".$changeTitle;
echo '<br>';
echo '<br>';
echo "SQL Update 1: ".$sql_update;
return $sql_update;
echo '<br>';
echo '<br>';
$result_update = mysqli_query($con,$sql_update);
if($result_update){
echo "Update Successful!";
}
else {
echo "Update Unsuccessful";
}
}
?>
<!--UPDATE FORM-->
<form class="form" method="post">
<label for="titleChange" class="sr-only">VCR Name</label>
<input type="text" name="titleChange" class="form-control" placeholder="VCR Name" required="" autofocus="" autocomplete="off">
<label for="sDescChange" class="sr-only">Short Description</label>
<input type="text" name="sDescChange" class="form-control" placeholder="Short Description" required="" autofocus="" autocomplete="off">
<label for="lDescChange" class="sr-only">Long Description</label>
<input type="text" name="lDescChange" class="form-control" placeholder="Long Description" required="" autofocus="" autocomplete="off">
<label for="priceChange" class="sr-only">Price</label>
<input type="text" name="priceChange" class="form-control" placeholder="Price" required="" autofocus="" autocomplete="off">
<button name="alter" type="submit">Change</button>
</form>
</content>
</body>
</html>

Answer 1

Your PHP code refers to a POST variable that doesn't exist:
$vcrName=$_POST['name'];
In your update form, you need to pass it as a hidden value:
<input type="hidden" name="name" value="<?=htmlspecialchars($vcrName)?>"/>
It's not clear if these are two separate PHP scripts (or if so, why they are) so you may need to put in a database call to get that value. From a user interface point of view, one is typically given the existing values when updating a record anyway. This would mean getting the data and giving each form element a value attribute.