Tracking incoming inventory parts from multiple item receipts
I am a contractor who inventories most of there products to be sold. I am attempting to to track from PO(stock ordered ) to item receipt (Stock received). I have a diagram that goes from PO Table to PO Line item table to track each individual part ordered. Then, I have a table Item Received that is related to the PO To Track the different shipments received to fulfill the PO. Here is where I start stumbling. Since all line items or all the quantities of each line item are not necessarily fulfilled on one item receipt is the reason I have an additional table for item receipts. What I do not see is how , since each PO and each PO line item can have multiple item receipts, how I can Track Each line item from the PO to see if it has been fulfilled. I have seen other examples where they do not track the individual item receipts but I would like to because these item receipts are generally turned into bills when they are received.
Any input would be great as I also want to use the same methods for outgoing to the different jobs