We all are know about the indexes and concept of it. As well as types of the indexes.During working one query optimization, i got suggested by SQL Server Optimizer with index creation and that index was Covering index.
What is covering index?
It is an additional index with include columns in definition which are exists in select list. Per msdn and book online, The term covering index does not mean a separate kind of index having a different internal structure. Rather, this term is used to describe a certain technique that is used to improve performance . It will better if we go through the demo and example. Let us start with objects creation,