Why might a database administrator choose NOT to create a single column index on a column with very few distinct values?

hard📝 Conceptual Q10 of 15

SQL - Indexes and Query Performance

ABecause the column cannot be indexed if values repeat

BBecause the index provides little speed benefit and uses extra space

CBecause the index will cause data corruption

DBecause the index will automatically delete duplicates

Step-by-Step Solution

Solution:

Step 1: Understand index usefulness related to distinct values
Indexes are most effective when columns have many unique values.
Step 2: Consider columns with few distinct values
Such indexes rarely improve query speed but consume storage and maintenance resources.
Final Answer:
Because the index provides little speed benefit and uses extra space -> Option B
Quick Check:
Low distinct values = low index benefit [OK]

Quick Trick: Avoid indexing low-cardinality columns to save space [OK]

Common Mistakes:

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