[Solved] Which of the following best describes the benefit of using a covering index? — Ans: It reduces the number of disk reads by avoiding table access | SQL

SQL - Indexes and Query Performance

Which of the following best describes the benefit of using a covering index?

AIt reduces the number of disk reads by avoiding table access

BIt increases the size of the table

CIt slows down query performance

DIt removes the need for any indexes

Step-by-Step Solution

Solution:

Step 1: Understand disk reads in query execution
Queries often read data from the table after using an index, causing extra disk reads.
Step 2: How covering index helps
A covering index contains all needed columns, so the query can get data directly from the index, reducing disk reads.
Final Answer:
It reduces the number of disk reads by avoiding table access -> Option A
Quick Check:
Benefit of covering index = fewer disk reads [OK]

Quick Trick: Covering index speeds queries by skipping table reads [OK]

Common Mistakes:

Master "Indexes and Query Performance" in SQL

9 interactive learning modes - each teaches the same concept differently

More SQL Quizzes

Which of the following best describes the benefit of using a covering index?