I have a problem with a loop in my database structure. I have 2 data feeds and a mapping table:
Feed 1
Account
Currency
SourceSystem
Amount
Feed 2
Account
Currency
SourceSystemID
Balance
MappingTable:
SourceSystem
SourceSystemID
Rather confusingly, there are many SourceSystemID's to one SourceSystem.
This structure creates a synthetic key consisting of Account and Currency, and also creates links via the mapping table for SourceSystem to SourceSystemID - and hence a loop.
I guess to get rid of the loop I need to do some sort of lookup on the mapping table when I load Feed2 so that I can add SourceSystem to that set of data and thereby create a synthetic key consisting of Account, Currency and SourceSystem.