Data Warehouse Fact

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A Data Warehouse Fact is a database value that represents a fact about the managed entity or system.



References

2020

  • (Wikipedia, 2020) ⇒ https://en.wikipedia.org/wiki/Data_warehouse#Facts Retrieved:2020-2-28.
    • A fact is a value, or measurement, which represents a fact about the managed entity or system.

      Facts, as reported by the reporting entity, are said to be at raw level; e.g., in a mobile telephone system, if a BTS (base transceiver station) receives 1,000 requests for traffic channel allocation, allocates for 820, and rejects the remaining, it would report three facts or measurements to a management system:

* tch_req_total = 1000
* tch_req_success = 820
* tch_req_fail = 180

Facts at the raw level are further aggregated to higher levels in various dimensions to extract more service or business-relevant information from it. These are called aggregates or summaries or aggregated facts.

For instance, if there are three BTS in a city, then the facts above can be aggregated from the BTS to the city level in the network dimension. For example: * tch_req_success_city = tch_req_success_bts1 + tch_req_success_bts2 + tch_req_success_bts3 * avg_tch_req_success_city = (tch_req_success_bts1 + tch_req_success_bts2 + tch_req_success_bts3) / 3