Question

What is an index? What are the advantages and disadvantages of using indexes? How do you use SQL to create an index?

Answer 1

Answer:

In DBMS, an index is a physical structure that stores the values for a specific column in a table. An index can be used to extract specific information from data and access records within a table more quickly without having to scan the whole table.

An Index can be made up of one or more columns of a table and each index maintains a list of values within that field that are sorted in ascending or descending order. Indexes cannot be seen by the users, but they are just used to speed up the queries and improve the performance of a database application