RE: Delete + Insert versus Update

Plus, if INSERT/DELETE executed from the app, it's an additional trip to
the database through SQL*Net, when comparing to UPDATE.

Igor

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ric Van Dyke
Sent: Thursday, February 16, 2006 10:54 AM
To: norman.dunbar@xxxxxxxxxxxxxxxxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx;
peters@xxxxxxxxx
Subject: RE: Delete + Insert versus Update

Also don't forget all the redo generated.  

A delete and reinsert could easily be 4+ times more expensive then an
update. 

Ric Van Dyke
Hotsos Enterprises
Cell 248-705-0624
-----------------------
Hotsos Symposium, be there:
http://www.hotsos.com/portal/events/SYM06
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Norman Dunbar
Sent: Thursday, February 16, 2006 10:34 AM
To: oracle-l@xxxxxxxxxxxxx; peters@xxxxxxxxx
Subject: Re: Delete + Insert versus Update


Peter,

My initial, off the top of my head, thought is simple :

in an UPDATE, the undo holds the before 'image' of the changed columns.
In a DELETE, the whole row is in the undo.
An INSERT, as far as I remember, holds the rowid as all it has to do is
delete the row.

So straight away there's a difference. 

As for indexes, an UPDATE is a DELETE/INSERT anyway.

As ever, untested (yet) !


Cheers,
Norman.




Norman Dunbar.
Contract Oracle DBA.
Rivers House, Leeds.

Internal : 7 28 2051
External : 0113 231 2051


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