Intermediate
Database Management Systems
Q59 / 100
What is a covering index?
Correct! Well done.
Incorrect.
The correct answer is B) An index containing all columns needed by a query, allowing the query to be satisfied entirely from the index without touching the table data
B
Correct Answer
An index containing all columns needed by a query, allowing the query to be satisfied entirely from the index without touching the table data
Explanation
A covering index includes all SELECT, WHERE, and JOIN columns for a query. The query can be answered from the index alone (index-only scan), avoiding expensive heap fetches.
Progress
59/100