Re: dual table - 9iR2

From: Hans Forbrich <forbrich_at_yahoo.net>
Date: Wed, 15 Sep 2004 02:56:20 GMT
Message-ID: <obO1d.26704$XP3.21689@edtnps84>

Hans Forbrich wrote:

> Oradba Linux wrote:
>

>> I am curious about the behavior of dual table in oracle 9iR2 . It looks
>> like when selecting from dual, implicitly where rownum=1 is added .
>> I am just curious about how it works .

>
> DUAL is a table provided to give you exactly one row and one column.
>
> Mucking with the contents can be dangerous to the health of your database
> and many applications written for Oracle. As a matter of fact, it's so
> important it's owned by the one userid, SYS, that should only be used in
> extreme cases such as startup, shutdown and emergency maintenance.
>
> In answer to your implied question 'What is ROWNUM?' ... it is a
> pseudo-column generated by the RDBMS engine at run time.
>
> Since this is explained in the Concepts manual at http://docs.oracle.com,
> I can only conclude you have not had a chance to read that ... sad

Apologies for jumping to conclusions here. I've had some bad experiences with people changing DUAL in older systems.

Counter question - have you noticed whether the behaviour is duplicated in any other client? Seems like the kind of thing for a RLS policy. Received on Tue Sep 14 2004 - 21:56:20 CDT