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What's the role of surrogate keys in dimensional modeling?

SQLhard0.5 min readPremium
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Low
Asked at 1 company
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487
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130E|271M|86H
in this category
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1,863
across 7 categories
Asked at these companies
Microsoft
Key Concepts Tested
etljoin
Expert AnswerPremium
98 wordsInterview-ready
Surrogate keys are system-generated unique IDs (e.g., auto-increment) for dimension rows. **Why they matter**: Natural keys change (customer ID rebrand, source system merge); surrogates are stable. (1) **SCD Type 2**: Same natural key, multiple rows (versions)—surrogate distinguishes them. (2) **Join performance**: Integer joins are faster than string/UUID. (3) **Integration**: Consistent IDs across sources with different natural key formats....
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