Re: serial data type

From: Jurij Modic <jurij.modic_at_mf.sigov.mail.si>
Date: 1997/08/29
Message-ID: <3406a88d.13752152@www.sigov.si>#1/1

On Thu, 28 Aug 1997 23:48:44 GMT, tkyte_at_us.oracle.com (Thomas Kyte) wrote:

>Wait a minute, a rowid for a row will *never* repeat *never* change.
>
>If you delete a row and reinsert it, as far as anyone is concerned it is simply
>NOT the same row.
>
>A rowid for a row will never change.
>
>If you delete it and reinsert a new rowid will change but that is *not* the same
>row.
>
>It identifies the row for any session, it does not guarantee that the row won't
>be deleted by someone....
>

Basicaly, I agree with you, but still :-) : it all depends on how you look at a row (logically or phisycaly). For example, if you export the table, drop it and reimport it again, the rowids for the rows might change but it is hard to say that the rows arent the same. They are not the same phisycaly, but logicaly they most certanly are.

I was arguing Steve's original statement:

  >...The rowid pseudo-column uniquely identifies   >the row in the table but only for the current session.

which is not true no matter how you look at it, because session has nothing to do with ROWIDS. During the same session a particular ROWID may identify more then one row. You may not rely on rowid to identify the same row next time you select it in the same session unless you lock the row.

>
>but anyway......
>
>For oracle8, the rowid is exposed externally in a base64 encoded string of 18
>characters (so as to not break existing apps that select the rowid, the length
>stayed the same). There are simple functions to break out pieces of a rowid in
>oracle8, consider the following block:
>...[SNIP]....
Thanks for the info. In the meantime I've already read the basic explanation in the docs, but your explanation and example is more then welcome.

>
>Thomas Kyte
>tkyte_at_us.oracle.com
>Oracle Government
>Bethesda MD

Regards,

---

Jurij Modic                             Republic of Slovenia
jurij.modic_at_mf.sigov.mail.si		Ministry of Finance
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The above opinions are mine and do not represent any official standpoints of my employer Received on Fri Aug 29 1997 - 00:00:00 CDT