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SCDs: Types of Slowly Changing Dimensions and their use cases

SQLeasy0.3 min readPremium
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Zen Data Shastra
Expert AnswerPremium
70 wordsInterview-ready
SCD types: 1—overwrite (no history); 2—add row (full history); 3—add column (previous value). Type 4—separate history table. Type 5—mini-dimension. Type 6—hybrid. Use 1 for corrections; 2 for audit/history; 3 for single previous value. Type 2 most common in DW. **Why it matters**: Design choices compound at scale—wrong approach can cause 100× overhead. **Scalability trade-offs**: Profile before optimizing; validate on sample then full....
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