Updating Rows
SQL Server 2008 performs row updates by evaluating the number of rows affected, whether the rows are being accessed via a scan or index retrieval and whether any index keys are being modified, and automatically chooses the appropriate and most efficient update strategy for the rows affected. SQL Server can perform two types of update strategies:
In-Place Updates
In SQL Server 2008, in-place updates are performed as often as possible to minimize the overhead of an update. An in-place update means that the row is modified where it is on the page, and only the affected bytes are changed.
When an in-place update is performed, in addition to the reduced overhead in the table itself, only a ...
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