Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...
Aggregate fact tables
1.
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