Re: Dual - multiple rows

May I know if there is any performance difference if I do not the SYS.DUAL and use my own dummy table?

By the way, can I revoke the insert and delete rights on SYS.DUAL from all users to set the table readonly?

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 6 Sep 1999 03:40:31 GMT, you wrote:

:>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 4 Sep 1999 03:53:13 GMT, you wrote:
:>

: [snip]

:>
:>: It will also put an index on DUAL which *may* mess up query plans in some
:>: unforseen way (so it is not recommended).
:>
:>If a table has only one record with unique index, I think most RDBMS query
:>optimizer wouldn't use that index in the query plan unless we have
:>special instruction.
:>

: as I said "some unforseen way".  I haven't done it.  I haven't tested it.  I
: have no idea what sort of side effects it might have here and there with
: different releases.  Rather then putting the constraints on dual (unsupported
: would probably be the quote support would use) -- I'd rather watch my DBA's.

:>
:>: The best way to ensure dual has 1 row is to keep control of who has DBA and make
:>: sure they are competent for the job.
:>
:>Can we add audit trail on the dual so that we can know which DBA have
:>modified the dual?
:>

: well, as long as your dba's dont use INTERNAL or SYS (which are never audited) : and each have their own userids, this would probably work.

:>
:>:>

: -- 
: 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

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http://www.washington.edu/pine/faq/ Received on Mon Sep 06 1999 - 08:37:30 CDT