User value used instead of PHP value in textbox - php

Question

I have a webpage thats purpose is to edit entries from a database. Its populated using PHP but i need the user to be able to change the value in these and update the database with the new value.
The problem im having is when i POST the data back from the form to the data base, the new information is NOT used, instead the PHP is. How do i fix this?
Each dropdown, text box and text field is populated from the text box using php:
<div class="col-lg-6">
<div class="form-group">
<label>Version</label>
<input type="text" class="form-control" name="forensic_tool_version" placeholder="Version" value="<?php
$session_name = $_SESSION['first_name']." ".$_SESSION['surname'];
$sql_query = "SELECT fi_forensic_tool_ver FROM asset_tracker WHERE asset_id = ? LIMIT 1";
$db_field = "fi_forensic_tool_ver";
$asset_id = $_GET['assetid'];
get_db_field($mysqli, $sql_query, $db_field, $asset_id, $session_name);
?>"/>
</div>
The get_db_field just gets the data and echos it to screen. This all works.
The user will then change one or more fields and click submit, where the following update will occur:
<!-- DATABASE INPUT - Input form elements into database -->
<?php
if(!empty($_GET['requestor']) ){
$asset_id = $_GET['assetid'];
$add_requestor = $_GET['requestor'];
$add_kc_number = $_GET['kc_number'];
$add_project_name = $_GET['project_name'];
$add_custodian = $_GET['custodian'];
$add_business_area = $_GET['business_area'];
$add_task = $_GET['task'];
$add_utl_reference = $_GET['utl_reference'];
$add_purchase_price_value = $_GET['purchase_price_value'];
$add_request_date = $_GET['request_date'];
$add_return_date = $_GET['return_date'];
$add_device_type = $_GET['device_type'];
$add_manufacturer = $_GET['manufacturer'];
$add_username = $_GET['username'];
$add_model = $_GET['model'];
$add_pinOrPassword = $_GET['pinOrPassword'];
$add_vf_asset_num = $_GET['vf_asset_num'];
$add_serial_num = $_GET['serial_num'];
$add_imei = $_GET['imei'];
$add_forensic_tool = $_GET['forensic_tool'];
$add_forensic_tool_version = $_GET['forensic_tool_version'];
$add_bitlocker_key = $_GET['bitlocker_key'];
$add_image_verified = $_GET['image_verified'];
$add_case_notes = $_GET['case_notes'];
$add_case_photos = $_GET['case_photos'];
if($query = $mysqli->prepare("UPDATE asset_tracker SET ci_requesting_employee=?, ci_kc=?, ci_project_name=?, ci_custodian=?, ci_business_area=?, ci_task=?, ci_utl_reference=?, ci_purchase_price_value=?, ci_date_requested=?, ci_date_returned=?, di_type=?, di_manufacturer=?, di_model=?, di_username=?, di_password=?, di_vf_asset=?, di_serial=?, di_imei=?, fi_forensic_tool=?, fi_forensic_tool_ver=?, fi_bitlocker_key=?, fi_image_verified=?, cn_notes=?, cn_photos=? WHERE asset_id = ? LIMIT 1")){
$query->bind_param('ssssssssssssssssssssssssi', $add_requestor, $add_kc_number, $add_project_name, $add_custodian, $add_business_area, $add_task, $add_utl_reference, $add_purchase_price_value, $add_request_date, $add_return_date, $add_device_type, $add_manufacturer, $add_username, $add_model, $add_pinOrPassword, $add_vf_asset_num, $add_serial_num, $add_imei, $add_forensic_tool, $add_forensic_tool_version, $add_bitlocker_key, $add_image_verified, $add_case_notes, $add_case_photos, $asset_id);
$query->execute();
$query->close();
echo "<script type='text/javascript'>alert('Asset updated Successfully');</script>";
}else{
echo "<script type='text/javascript'>alert('Cannot access database');</script>";
}
}else{
//echo "<script type='text/javascript'>alert('Post not set');</script>";
}
?>
Any help on this would be much appreciated!
Thanks!