Can anyone help me to understand how NAV tables are linked in SQL 2014.

I need to take a snapshot each day from NAV and merge with data from an older database to form a data cube in another SQL database for reporting on.
So I need to know how so I can quickly create queries to export just the data I need.

I can see how ITEM, SALES, PURCHASES, SUPPLIER, CUSTOMER are linked now I need to look at the ledger tables in order to see stock levels, customer purchase history etc etc.

Any help would be appreciated.

Thank you

Richard Elliott ( 2 days in to NAV )