Does anyone know if the Oracle system uses seperate ledgers for each currency or 1 multi currency ledger?

Answer 1

Oracle is a 'relational database' ..

Essentially this means that the underlying data is held in it's original form and processed to give you the view you wish to see.

If the Tables contain Currency items, and you generate a $$ view, then all non-$ items will be converted (using whatever rules you put in place) to give a uniform $ view.

If you generate a multi-currency view, each individual item will be shown in it's original (entered) currency.