Advanced
Big Data & Data Engineering
Q93 / 100
What is "dictionary encoding" in columnar storage, and when is it most effective?
Correct! Well done.
Incorrect.
The correct answer is A) Replacing repeated values with integer references to a dictionary of unique values, most effective on columns with low cardinality
A
Correct Answer
Replacing repeated values with integer references to a dictionary of unique values, most effective on columns with low cardinality
Explanation
Dictionary encoding stores unique values once and references them by small integer codes, yielding large compression gains for low-cardinality columns like country or status.
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93/100