Microsoft® SQL Server 2012 Unleashed

Updating Rows

SQL Server 2012 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

Not-in-place updates

In-Place Updates

In SQL Server 2012, in-place updates are performed as often as possible to minimize the overhead of an update. An in-place update means ...