oracle aide

December 30, 2014

Slow changing dimensions types 0-4

Filed under: Uncategorized — oracleaide @ 1:02 am

The common enumeration of  SCDs using types 0-7 encodes a single attribute — where the history is stored.

I think there is an obvious pattern for types 0-4 (and emerging mnemonics):

Type 0: history is stored nowhere.

Type 1: history is stored in the dimension itself, in a single current row (history with length of 1 means – no history).

Type 2: history is stored in the dimension itself, in extra rows (history length is 2+)

Type 3: history is stored in the dimension itself, in extra columns (something about 3rd dimension?)

Type 4: history is stored in a separate table.

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