Question

What are composite indexes?

(a) Are those which are composed by database for its internal use

(b) A composite index is a combination of index on 2 or more columns

(c) Composite index can never be created

(d) None of the mentioned

The question was posed to me in an interview.

I'd like to ask this question from Index Definition in SQL in section Indexing and Hashing of Database Management

Answer 1

The correct answer is (b) A composite index is a combination of index on 2 or more columns

Easiest explanation - A composite index is an index on two or more columns of a table.