Aggregate fact tables

2. Aggregates are precalculated summaries derived from
the most granular fact table(level of detail in the fact
table).
If the fact table is at the lowest grain
The facts or metrics are at the lowest possible level at
which they could be captured from the operational
system.
what is the Advantages of lowest grain?

3. Choose a simple STAR schema with the fact table at
the lowest possible level of granularity.
Assume four dimension table with most granular fact
table.
Operational system-single order, invoice, product and
so on.
Data warehouse- produce large result set(these
retrieve hundreds and thousands

7. Fact table size

9. Need for aggregates

11. Aggregating fact table

14. Three way