PS Overview
http://wolcottconsulting.com/documentation/Project%20Systems%20Structure%20Overview.pdf
PS Database Tables overview http://scn.sap.com/docs/DOC-28689
ECC PS Tables
PROJ Contains Projects
PSPNR is the Project ID
PRPS Contains WBS Elements
PSPNR is the WBS ID
PSPHI is the Project ID
AFVC Contains the Network Activities
VORN is the Activity
PROJN is the related WBS ID
AUFPL is the Network
CAUFV Contains the Networks
AUFPL is the Network