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Re: Rowid question

From: Thomas Kyte <tkyte_at_us.oracle.com>
Date: Thu, 03 Sep 1998 20:18:54 GMT
Message-ID: <3611f93a.113068483@192.86.155.100>


A copy of this was sent to "Kevin P. Fleming" <kfleming_at_access-laserpress.com> (if that email address didn't require changing) On Thu, 03 Sep 1998 19:56:58 GMT, you wrote:

>Thomas, is that true even if the row has to be migrated to a different block
>when it gets expanded later?

Yes -- if a row migrates, its rowid is still the old rowid (else indexes and snapshots would get *really* messed up). What happens is that we leave a 'forwarding' address for the migrated row at the old rowid location. when you access that row by rowid, it'll read the old block -- find that its moved -- and go to the new location.

Once a row is inserted, its rowid is constant.

>
>Thomas Kyte wrote in message <360bded1.106307201_at_192.86.155.100>...
>>A copy of this was sent to mtillberg_at_my-dejanews.com
>>(if that email address didn't require changing)
>>On Thu, 03 Sep 1998 17:27:02 GMT, you wrote:
>>
>>> Are rowid values guaranteed to be consistant over updates if the rows
>they
>>>point to aren't changed? For instance, I have a table that users can
>access
>>>in an editor. Although I don't care in what order the data is sorted
>>>(actually, I don't want it sorted by value), I want the data to show up in
>>>the same sequence everytime. Also, the users only access a few rows at a
>>>time. Here's the situation:
>>>
>>>User1 loads data into the editor.
>>>User2 loads data into the editor.
>>>User2 makes changes and commits.
>>>User1 makes changes and commits.
>>
>>yes, once a row is inserted -- its rowid is *never* changed.
>>
>>>
>>> I want to make sure that user1's data has the same rowids as when he
>>>started.
>>>
>>>-----== Posted via Deja News, The Leader in Internet Discussion ==-----
>>>http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum
>>
>>
>>Thomas Kyte
>>tkyte_at_us.oracle.com
>>Oracle Government
>>Herndon VA
>>
>>--
>>http://govt.us.oracle.com/ -- downloadable utilities
>>
>>---------------------------------------------------------------------------
>-
>>Opinions are mine and do not necessarily reflect those of Oracle
>Corporation
>>
>>Anti-Anti Spam Msg: if you want an answer emailed to you,
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Thomas Kyte
tkyte_at_us.oracle.com
Oracle Government
Herndon VA

--
http://govt.us.oracle.com/ -- downloadable utilities  



Opinions are mine and do not necessarily reflect those of Oracle Corporation  

Anti-Anti Spam Msg: if you want an answer emailed to you, you have to make it easy to get email to you. Any bounced email will be treated the same way i treat SPAM-- I delete it. Received on Thu Sep 03 1998 - 15:18:54 CDT

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