Choosing Your Strategy

Concepts: dmScdStrategy

Per-Attribute Strategy The most important concept: SCD type is chosen per attribute, not per table. A single dim_customer can have Type 1 on name (typo corrections do not need history), Type 2 on region (revenue attribution needs point-in-time accuracy), and Type 3 on segment (before/after comparison for a migration). The decision for each attribute: does anyone need the historical value? If the answer is 'yes, for reporting or audit,' use Type 2. If the answer is 'no, and keeping it creates useless rows,' use Type 1. If the answer is 'only the immediately previous value, for a specific comparison,' Type 3.