In addition each distinct aggregation level must

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Unformatted text preview: n Requirements #1 Aggregates must be stored in their own fact tables, separate from the base-level data. In addition, each distinct aggregation level must occupy its own unique fact table #2 The dimension tables attached to the aggregate fact tables must, wherever possible, be shrunken versions of the dimension tables associated with the base fact table. 03/15/10 03/15/10 Prof. Navneet Goyal, BITS, Pilani 44 Design Requirements #3 The base Fact table and all of its related aggregate Fact tables must be associated together as a "family of schemas" so that the aggregate navigator knows which tables are related to one another. #4 Force all SQL created by any end user or application to refer exclusively to the base fact table and its associated full-size dimension tables. 03/15/10 03/15/10 Prof. Navneet Goyal, BITS, Pilani 45 Storing Aggregates New fact and dimension table approach (Approach 1) New Level Field approach (Approach 2) Both require same space? Approach 1 is recommended Reasons? 03/15/10 03/15/10 Prof. Navneet Goyal, BITS, Pilani 46 Lost Dimensions 03/15/10 03/15/10 Prof. Navneet Goyal, BITS, Pilani 47 Collapsed Dimensions 03/15/10 03/15/10 Prof. Navneet Goyal, BITS, Pilani 48 Q&A Thank You...
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