Special Index Structures
SQL Server 2008 allows you to create several special kinds of indexes: indexes on computed columns, indexes on views, spatial indexes, full-text indexes, and XML indexes. This section covers the requirements and the structural differences of creating these types of indexes.
Indexes on Computed Columns and Indexed Views
Without indexes, some of these constructs—computed columns and views—are purely logical. There is no physical storage for the data involved. A computed column is not stored with the table data; it is recomputed every time a row is accessed (unless the computed column is marked as PERSISTED). A view does not save any data; it basically saves a SELECT statement that is executed again every time the data in the ...
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