What is the main purpose of using indexes in Azure SQL Database?

Using indexes in Azure SQL Database serves the primary purpose of facilitating fast data retrieval. Indexes function similarly to an index in a book, allowing the database engine to quickly locate the rows in a table that meet the criteria specified in a query. By reducing the number of data pages that need to be scanned during a query, indexes significantly enhance performance, especially for large datasets where full table scans would be time-consuming.

When an index is created on a column or set of columns, it allows the database to find data without having to look at every single row, which optimizes query execution time. This is particularly beneficial for queries that require sorting or filtering, as indexes can structure data to meet those requirements efficiently.

Other options, while important in different contexts, do not relate to the core functionality of indexes. For example, encrypting sensitive data is primarily concerned with data security rather than retrieval speed. Creating backups and managing service updates are operational tasks that don't involve the indexing mechanism. Thus, the essential role of indexes lies in increasing query response times and improving overall database performance.