[AccessD] How does SQL Server do updates

<<No other way to make it all work >>

  That is not the case.  Rollbacks within a RDBMS can be done in any number
of ways, one of which is to use a run unit journal file (a log of the
changes).  I can easily record changes as they are made to a file and update
data in place as I am doing so. 

 If a rollback needs to occur, I can read the log file backwards and restore
the data.  Once a transaction is committed, some save that data to a after
image journal, which makes roll forwards possible from a full backup.  In
some systems, the function of a run unit journal and the after image data is
stored and managed in the same file, but the functionality is still there.

Jim.

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Arthur Fuller
Sent: Tuesday, October 09, 2012 05:05 PM
To: Access Developers discussion and problem solving
Subject: Re: [AccessD] How does SQL Server do updates

Precisely my point, Jim. In-situ updates by definition destroy data and
prevent rollbacks; hence the delete-then-insert scenario, without which a
rollback would be impossible. Thus, UPDATE is a glorified term for DELETE
then INSERT. No other way to make it all work. Nuff said,,, or perhaps for
the sake of performance you would prefer to sacrifice RollBack.

A.
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