A database
index is a data structure that improves the speed of data retrieval operations.
Indexes are necessary for high performance read operations for frequently used
queries. Without indexes, database table/collection will be scanned fully to
select required data that match the query statement. Full database table/collection scan is very slow operation for a huge
amount of data. But indexes can increase read operation performance to point to
exact records without necessity to scan all the records in storage.
Indexes are
very useful and essential for database storage at the cost of additional storage
space and influence on write/update/delete operations speed.
Fundamentally,
indexes in MS SQL
Server and MongoDB are similar.
But, of course there are a couple of differences between them.
