Re: Get a RowID with Oracle 8.1.5

A copy of this was sent to "Dirk Poppke" <poppke_at_iug.cs.uni-dortmund.de> (if that email address didn't require changing) On Thu, 20 Jan 2000 10:06:53 +0100, you wrote:

>Hello!
>
>I've got a simple newbee question:
>
>I wan't to get a unique rowid for a row in a table. Till now,
>i used a sequence, but the sequence didn't reuse numbers
>which are set free again (maybe by a delete Statement).
>

since a sequence is an Oracle number upto 28 digits a sequence has an extremely large range. Reuse of a sequence number should never be needed if you just want to get a unique identifier for a row. It'll take a *really* long time to exhaust the values in a sequence -- even if you lose millions or billions of them you'll only have lost a small percentage of

9,999,999,999,999,999,999,999,999,999

There are really no performant, reliable alternatives. Every other attempt i've ever seen causes serialization.

>The pseudo - column RowID works easier, but you can't
>migrate them to another DB.
>

and rowids (as of Oracle8i, release 8.1) can change for a row after its been inserted in certain cases (2 that i know of). You should not permanently store a rowid in another table anymore. You can use rowids for short transactions (eg: web transactions from page to page or as forms does to implement its locking scheme).

>Is there a better solution than this two ways?
>
>Thanx in advance,
>Dirk
>

--
See http://osi.oracle.com/~tkyte/ for my columns 'Digging-in to Oracle8i'... Current article is "Part I of V, Autonomous Transactions" updated June 21'st  

Thomas Kyte                   tkyte_at_us.oracle.com
Oracle Service Industries     Reston, VA   USA

Opinions are mine and do not necessarily reflect those of Oracle Corporation Received on Thu Jan 20 2000 - 10:25:08 CST