Intermediate
Database Management Systems
Q47 / 100
What is a hash index?
Correct! Well done.
Incorrect.
The correct answer is B) An index using a hash function to map keys to bucket positions, providing O(1) equality lookups but not supporting range queries
B
Correct Answer
An index using a hash function to map keys to bucket positions, providing O(1) equality lookups but not supporting range queries
Explanation
Hash indexes provide O(1) equality lookups but cannot support range queries, ORDER BY, or partial key lookups. In PostgreSQL they're useful for equality-only workloads; MySQL InnoDB doesn't support them.
Progress
47/100