Whenever you roll back a transaction, it nullifies the effect of every command you’ve executed since
you started the
transaction. But what happens if you want to roll back only
part of an ongoing transaction?
SQL Server handles this
with a feature called savepoints.
Savepoints are markers
that act like bookmarks. You mark a certain point in the flow of the
transaction,
and then you can roll
back to that point. You set the savepoint using the
Transaction.Save()
method. Note that the
Save() method is available only for the SqlTransaction class, because it’s
not
part of the standard
IDbTransaction interface.
原文：http://www.cnblogs.com/lthxk-yl/p/3658593.html