Regarding the AggregationId...
I use the HS_IHE_ATNA_Repository.Aggregation table a lot. Someone just referred me to the HS_IHE_ATNA_Repository.Document table, which has an AggregationId column.
I assume that column references the ID column in the .Aggregation table. If so, does this mean that if the same document was requested 1,000 times that there will be 1,000 entries for it in the .Document table? This seems inefficient to me. Why not have one record in the document table and have a DocumentId column in the Aggregation table?