after record added delete records other table

Hi,
I have two tables

1 stock table with a number_part column

2 table export with a number_part column

and wanted to add the data in export to delete it from stock. it's possible?
I did tests with the afetr aded event

with this code

global $conn;
$StockData = $pageObject->getMasterRecord(); // Returns an array of the master record

$StockData["part_stock"]; //Get current stock count
IF($values["mvt_type"] == "I")

{

$NewStock = $StockData["part_stock"] + $values["mvt_qty"]; // Add value to current stock

}

ELSE

{

$NewStock = $StockData["part_stock"] - $values["mvt_qty"]; // Deduct value from current stocck

}
//Update the new stock count to the parent stock part number

$StockUpdate = "UPDATE stock SET part_stock = ".$NewStock." where part_no = ".$values["part_no"]."";

db_exec($StockUpdate,$conn);