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Why should raw source data be preserved untouched during cleaning?

  1. A So every transformation can be traced back and re-run if a decision changes
  2. B To satisfy storage quotas
  3. C To speed up queries
  4. D Because cleaning is irreversible in SQL
Answer

So every transformation can be traced back and re-run if a decision changes

Cleaning decisions should also be documented, or the analysis cannot be reproduced or defended later.

All Data MCQs

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