Microsoft® SQL Server™ 2005: Applied Techniques Step by Step

Conclusion

In this chapter, you have learned how SQL Server stores and accesses data with and without indexes. Through analyzing query plans and I/O statistics, you have seen how important it is that the right indexes exist to optimize performance. You have learned when and how to use different index types (summarized in the table opposite) and how to maintain them.

Index Types

Clustered index	Stores the table data rows in the leaf level of the indexes. Provides fast sorted and range access based on the index keys. Only one clustered index can exist on a table.
Nonclustered index	Provides fast index seek operations based on index keys and can be created as covered indexes. Up to 249 can exist on a table.
Computed column index	Stores computed columns ...