Re: ROWID question?

Denham,

At the risk of going slightly off-topic. If the number of rows you are expecting to keep is relatively small, it might be much quicker to create a temporary table with the rows you wish to keep, truncate the main table and re-insert the rows back in. Of course this approach presents issues of its own.

Also, the comments about replacing rowid with the date column are very valid - There is no way to guarantee that the row with the newest date has a larger rowid. I always believe you should treat rowid's as a magical number - they are fine for referring to directly, but not things like min (), max() or any kind of manipulation.

Good luck.

                                                                                                                   
                    Denham Eva                                                                                     
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                    23/10/2002                                                                                     
                    00:49                                                                                          
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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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