On your update page the query is looking for a URL parameter named id_inventory. It seems that the query is setup correctly to work with this parameter. The problem that I can see on your update page is that you do not have any of the values from your recordset bound as the values for the form elements. For example your title form element, you have the value like this:
php:
value="<?php echo((isset($_GET["invalid"])?ValidatedField("hbinventoryUpdate","title"):"")); ?>"
It is set to show the value that you entered if the validations fail, but it is not setup to show you the default value for that record in the db. You will need to add in your recordset binding in here where the empty double quotes are like this:
php:
value="<?php echo((isset($_GET["invalid"])?ValidatedField("hbinventoryUpdate","title"):$row_WADAhb_inventory['title'])); ?>"
This should get the elements to show the value from the recordset when the page loads.
