Why aggregate is used in dimensional model of data warehouse?

Options
- To take the dimension and change its granularity
- To retrieve data from an operational system
- To store data in one operational system
- All of the above

CORRECT ANSWER : To take the dimension and change its granularity

Discussion Board
Aggregate

Aggregates are used in dimensional models of the data warehouse to produce dramatic positive effects on the time it takes to query large sets of data. A more common use of aggregates is to take a dimension and change the granularity of this dimension. When changing the granularity of the dimension the fact table has to be partially summarized to fit the new grain of the new dimension, thus creating new dimensional and fact tables, fitting this new level of grain. Aggregates are sometimes referred to as pre-calculated summary data, since aggregations are usually pre-computed, partially summarized data, that are stored in new aggregated tables.

Prajakta Pandit 03-15-2017 01:57 AM

BODS

Good

Reddy 10-4-2014 08:22 AM

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