Categories and mappings

Module 5 quiz

Practice questions: choose an answer and check it to see the explanation. Nothing here is timed or graded.

1. 1. Why normalize case and spacing before mapping?

   Dictionaries can't hold uppercaseIt keeps the approved dictionary short and catches variants like "E-mail "Mapping is case-insensitive anywayIt is required by SQL
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2. 2. A channel value "emial" is not in the approved dictionary. What should happen?

   Map it to email because it is closeQuarantine it as unmapped and propose a dictionary addition for reviewDrop the rowKeep it as a new category
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3. 3. Why should a category mapping be stored as data (a table) rather than as scattered IF statements?

   Tables are fasterA mapping table can be reviewed, versioned and reused across toolsIF statements can't handle textIt isn't needed
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4. 4. You lowercase and trim channel, then map using a dictionary whose keys are "Email" and "Phone". What happens to "email"?

   It maps to EmailIt stays unmapped because the dictionary keys weren't normalized the same wayIt becomes missingIt raises an error
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5. 5. What makes a mapping reversible?

   Using numbersKeeping the original value next to the mapped valueSorting the outputLowercasing
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6. 6. Two source spellings could map to two different approved categories. What should you do?

   Pick oneAsk the data owner and record the decision in the mapping tableMap to bothDrop the rows
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7. 7. A mapping has 7 entries; the data has 9 distinct normalized values. How many values end up unmapped at most?

   0279
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