Sap License types post will help you understand the different kind/ type of license in SAP. In SAP, there are Basic License Types (named), Special License Type and Software engines.
How to link STKO and STPO : Find the link between STKO and STPO is a common requirement in SAP PP for example. This post will guide through the SAP Tables Diagram for SAP BOM.
Link between PLKO and PLPO for Routine in SAP will be explain in this post with the definition of each tables involved and a sample ABAP Code to retrieve for a Production Version the Routine.
Function Module SAP Tables storing information about SAP function modules. SAP Table name in which function module and function group are in the system.