What is the diffrence between composite index and covering index in Sql Server ?
+2
A:
A covering index is a composite index that contains every column you are currently retrieving with your select statement and that participates in the where clause. It is one of the best ways to improve query performance substantially.
Otávio Décio
2010-04-07 20:02:11
A:
A covering index is a composite index that covers (hence the name) all columns that are necessary to fulfill a query or a join condition.
There is nothing special about SQL server here, these are generic designations.
Tomalak
2010-04-07 20:03:59
Indexes aren't covered by ANSI standard - it's luck that vendors haven't named the functionality differently.
OMG Ponies
2010-04-07 20:31:05
@OMG Ponies: I suspect that the names were coined by computer scientists and not by DB vendors.
Tomalak
2010-04-07 20:36:56