Re: what is Roll back

Oh cool, a newbie! Welcome to the world of Oracle! ;-)

When a transaction changes (insert/update/delete) data in the database, it records the before image of the data to be changed, in the rollback segment. There are two reasons:

1.) So that if the transaction errors, or the user wants to abort it, Oracle can 'rollback' the changes.
2.) To maintain read consistency. If you are updating data that someone else is reading, Oracle needs to be able to provide a read consistent view of that data to the reader.

Hope that helps,

-Mark

In article <BieY6.2759$3d3.205403_at_bgtnsc05-news.ops.worldnet.att.net>, "Gowdhaman Rajan" <Gowdham_at_worldnet.att.net> wrote:

> Hi,
> Iam have little bit confusion about Roll back segment.If anyone knows
> .pls explain me in details.
>
> thank,
>
>
Received on Thu Jun 21 2001 - 01:10:48 CDT