Inventory management calculations

Still struggling to figure out how to do calculations in my inventory app.

Short overview:
I have a database table with all parts in my inventory, these are intended for assembly of different products.
I have a table for each of the products where each row holds a specific part and its quantity, so its basically a “recipe” of the product.

I want to subtract all used parts from my inventory after a product has been put together.

Not sure exactly, but my suggestion would be to have a Bot or action that goes in and updates the stock level everytime you add a part

Simon, 1minManager.com