Oracle-L: RE: ROWID question?

From: Fink, Dan <Dan.Fink_at_mdx.com>
Date: Tue, 22 Oct 2002 09:49:34 -0800
Message-ID: <F001.004F01E5.20021022094934@fatcity.com>

The script you are using will achieve your goal. It's a pretty common one to remove dups.

ROWIDs will be reused once Oracle reinserts a row into the 'hole'. However, for the duration of the transaction, this will not be the case. Since the transaction could be rolled back, the 'space' cannot be reallocated. Imagine what would happen if there were two rows with the same rowid. Not possible with Oracle's tx architecture (excepting a really nasty bug, of course).

Dan Fink

-----Original Message-----
Sent: Tuesday, October 22, 2002 8:49 AM
To: Multiple recipients of list ORACLE-L

Hello Gurus

Does Oracle reuse ROWID "numbers", once a delete of a row has been done?

The reason I ask is because, I need to delete duplicate records from a very large table.
However I must keep the newest date in one of the date columns.

If oracle does not reuse the ROWID this would be very simple. Here is my sql:

DELETE FROM tablename a
WHERE ROWID <> (SELECT MAX(ROWID)

                        FROM tablename b 
                        WHERE a.col1 = b.col1 
                        AND a.col2 = b.col2 
                        AND a.col3 = b.col3);

However if Oracle does reuse ROWID's then I have a serious sql problem :) All the examples I have of deleteing duplicates use the ROWID. If anyone has a suggestion on how else to do this I would be most grateful.

Otherwise answer on my main question would be fine. Many Thanks
Denham Eva

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Author: Fink, Dan
  INET: Dan.Fink_at_mdx.com

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Received on Tue Oct 22 2002 - 12:49:34 CDT