SAP B1 Inventory tables Update

Hi,

Can anyone explain to me the link between the stock transaction tables in SAP business one? ie;

OIVL

PDN1

INV1

Can you directly update OIVL via DTW and would this then be reflected in PDN1 and INV1? Or do you have to upload to the separate tables and OIVL is just a summary table?

Thanks in advance for your help!

Mark