Update to the data structure

Someone suggested to break the units and denomination into two 'events'.  So, we would have:

I Offer 100
My Offer-units $
My Terms 'plane ticket to BKK'
His Terms 150
My Offer 130
He Agrees.

So, the data structure has 6 columns:
EventID (GUID or similar)
TransactionID (GUID or similar)
EventType (text)
CommerceID (user defined)
Description (text)
TimeStamp (date time)