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RE: How to prevent DUAL having more than 1 row

From: Mohammad Rafiq <>
Date: Fri, 08 Sep 2000 15:14:54 EDT
Message-Id: <>

Has somebody imported dmp with system data and with rows=y ignore=y. This is one of the possible reason which happened to us in our early days with Oracle version 5(1988-89) when ignore=y/n option was not available. Regards

From: "Steve Adams" <> Reply-To:
To: Multiple recipients of list ORACLE-L <> Subject: RE: How to prevent DUAL having more than 1 row Date: Thu, 07 Sep 2000 07:15:42 -0800

Hi Babu,

I can't tell you how this happened, but I can suggest an unsupported way of making sure that it never happens again. The APT script "replace_dual.sql" at can replace the SYS.DUAL
table with a view onto X$DUAL. Once that's done, it will not be possible for extra rows to appear in DUAL again. From a performance point of view, there is a
slight increase in the parse overhead, but a slight reduction is the execution
cost of statements that refer to DUAL. Once again, this is unsupported - mentioned for information only.

@ Regards,
@ Steve Adams


@ Going to OpenWorld?
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-----Original Message-----
Sent: Thursday, 7 September 2000 21:33

In one of the databases here, count(*) from dual gave me 3. I deleted two rows
based on the rowid's and now things are working fine. I was wondering how it could happen in the first place. No, no one logging in as SYS inserted this. Then how?

Author: Steve Adams

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Received on Fri Sep 08 2000 - 14:14:54 CDT

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