Jeff Moden (2/15/2011)
Since I'm not an expert on indexes that you good folks are, can you confirm that the bolded statements in the above quote are, depending on whether it's a covering index or not, incorrect... or not? I realize that data is stored in the index but that data is actually used if it's a covering index.
A nonclustered index does not just contain an address of the actual row. It contains the index key columns, any include columns defined and either the clustered index key or the RID, depending whether the base is a heap or a cluster. The clustered index key/RID can be considered the 'address' of the row.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability