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SCD Implementation in ETL

SQLeasy0.4 min readPremium
Frequency
Low
Asked at 1 company
Category
487
questions in SQL
Difficulty Split
130E|271M|86H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
Nagarro
Key Concepts Tested
etlspark
Expert AnswerPremium
81 wordsInterview-ready
SCD in ETL: Type 1—overwrite; Type 2—add row with history; Type 3—add column. Implement Type 2: compare incoming to current by natural key; if changed, close current (end_date), insert new. Use MERGE or incremental logic. Tools: dbt incremental, Spark MERGE, SSIS SCD transform. Key: surrogate key, effective/expiry dates, is_current flag. **Why it matters**: Design choices compound at scale—wrong approach can cause 100× overhead....
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