Re: Dual - multiple rows

From: Norris <johnnie_at_cooper.com.hk>
Date: 4 Sep 1999 03:53:13 GMT
Message-ID: <7qq539$26ie$1@adenine.netfront.net>

How can we guarantee dual has only one row? If not, then it would not be safe to use select 'abc' from dual.

Thomas Kyte <tkyte_at_us.oracle.com> wrote:

> A copy of this was sent to Norris <johnnie_at_cooper.com.hk>
> (if that email address didn't require changing)
> On 3 Sep 1999 09:49:53 GMT, you wrote:

>>Can we add trigger on dual to make sure that it can only have one record?

> No you cannot. You cannot put triggers on objects owned by SYS and dual is > owned by SYS.

>>
>>Thomas Kyte <tkyte_at_us.oracle.com> wrote:
>>> A copy of this was sent to g.renfrew_at_acca.org.uk
>>> (if that email address didn't require changing)
>>> On Thu, 02 Sep 1999 10:11:43 GMT, you wrote:
>>
>>>>Hi everyone,
>>>>
>>>>I'm running 7.3.2.3 on Solaris 2.6 and came across a bit of a weird
>>>>problem with the DUAL table. When I selected from DUAL it always
>>>>returned two identical rows. On all my other databases I would only
>>>>ever expect one row returned, as is normal. This problem caused a
>>>>couple of errors with "ora-1422: exact fetch returns more than
>>>>requested number of rows". When I did "select * from dual" it returned
>>>>the following:
>>>>DUMMY
>>>>-----
>>>>X
>>>>x
>>>>
>>>>Since all my other databases returned only 'X' I deleted from dual
>>>>where DUMMY = 'x' and everything is ok now.
>>>>Any ideas on how an extra row would appear in DUAL?
>>>>
>>
>>
>>> somebody inserted it (one of your DBAs probably).
>>
>>> DUAL is a real table -- its not special or anything. If it has no rows --
>>> that'll cause havoc. If it has >1 row, same thing.
>>
>>>>Best Regards
>>>>Graeme Renfrew
>>>>DBA
>>>>ACCA
>>>>Glasgow
>>>>
>>>>
>>>>Sent via Deja.com http://www.deja.com/
>>>>Share what you know. Learn what you don't.
>>
>>
>>> --
>>> See http://govt.us.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

> -- 
> See http://govt.us.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

--
Have several nice days...

---

Opinions are mine and do not necessarily reflect those of the Corp.

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Received on Fri Sep 03 1999 - 22:53:13 CDT