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Explain Data Modeling SCD Types (Type 1, 2, 3).

SQLmedium0.5 min readPremium
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Asked at 1 company
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EY
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Expert AnswerPremium
103 wordsInterview-ready
**Architectural Logic**: SCD types trade history depth vs storage and complexity. **Type 1**: Overwrite; no history. Use when history irrelevant (typo correction). **Type 2**: Full history; new row on change; effective_from, effective_to, current_flag. Use when history needed (customer address, department). **Type 3**: Limited history; previous value in column. Use when only last change matters. **Implementation**: Type 1 = UPDATE; Type 2 = INSERT new + UPDATE current; Type 3 = UPDATE shift....
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