Referring to multiple fields throught different tables/db's properly

[VanCity]

Trying to manage inventory:
Need partno X qty to be properly effected by adding po's received qty, (logging backordered qty), alloacating (removing from inventory partno X qty) workorder amounts and when the corresponding invoice is made from the work order, removing the allocated amount in enventory at that time.
Right now I can track the rec'd amount to add to Stock Qty in inventory for one PO only, I need this to apply to any partno on any PO
Hope thats enough info for you.
Been a while since I've been on this forum (different user name) - it's never failed me yet !!

 

[VanCity]

Perhaps a clearer explanation here:
Tracking quantities of a given part number to maintain inventory.
Trying to make inventory consolidations: databases that effect any given "part number's qty field" in inventory database are:

"PO's received field" in PO database(adds to "stock on hand field" qty in Inventory database),

"Backordered PO items field" in PO database(adds to "Stock BO'd field" in Inventory database),

"Work Orders Quantity field" (for any partno)in Work Orders database (removes from "stock on hand field" in Inventory database and puts into "allocated field in Inventory), invoiced work orders remove part # qty from "allocated field" in Inventory.

 

[VanCity]

So far I can only update BO'd Qty (in inventory) for any given part number from the first occurance only in the PO BO'd field (doesnt matter if it is the first, second last, etc PO where the part number is, it only picks the first occurnace), how do I get it to "scan" all PO's for a BO for any given part number?