Many aggregates can be defined for one base star schema Some dimensions could be lost, some shrunken Created for performance reasons Can be made transparent to the user Customer Date Price Cost Tax Qty Product Transaction Store Transaction-level star Jan 2003 91.4904 Ron McFadyen

Aggregates Month Customer Date Product Product Transaction Store Store Price Cost Tax Qty Price Cost Tax Qty Product Product Transaction Store Store Transaction-level star Aggregate star with: lost dimensions (transaction, customer) shrunken dimension (month) metrics are accumulated over the transactions, customers, month Jan 2003 91.4904 Ron McFadyen

Provide “-to-date" measures, such as monthly status values, examples: Snapshots Provide “-to-date" measures, such as monthly status values, examples: Starting/ending balances for the month Quantity on hand at the end of the month These could be calculated from an underlying transaction-level star, but the calculations/processing could be prohibitive. Has similarities to an aggregate in that some dimensions could be lost, some shrunken Jan 2003 91.4904 Ron McFadyen