Re: Rebuilding Indexes, Now: KEEP INDEX

On the contrary, Connor, it's of tremendous political value, if not practical ;)

Besides, the fact that unique indexes may have null values whereas PKs can't.

I have found the use in this case:

In the US, we all have a Social Security Number (SSN), a sort of like a birth mark ever since we were born. An insurance carrier might have the SSN as a primary key and that would work out fine, till one fine day they decide to accept visitors in a new plan for temporary health insurance coverage. These people have no SSN, making it null. Suddenly the PK on SSN was dropped and a synthetic key containing SSN and a sequence number (999999999 for SSN is null) was chosen as SSN; but the SSN index was kept since that was unique anyway. With 40 GB tables (in all) this option to keep index came pretty handy.

Thanks.

Arup

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Sunday, December 29, 2002 3:23 PM

> I'm a little doubtful about the value of 'keep index'.
>
> Consider the scenarios:
>
> unique constraint, non-unique index:
> - "keep index" redundant because its kept anyway
>
> unique constraint, unique index:
> - "keep index" redundant because effectively retains
> the constraint anyway (because you still can't insert
> dups)
>
>
> So far, the only use for KEEP INDEX I've found is the
> scenario where you:
>
> - decided that column(s) X was the primary key
> - created a unique index on it
> - created a primary key constraint on it
> - loaded the data
> - decided actually X was NOT the primary key, just a
> unique value
> - decided that X could allow nulls as well
> - dropped the primary kept, kept the index and then
> added a unique constraint...
>
> I would contend that this is a rare occurrence ?
>
> Cheers
> Connor
>
>
> --- Rachel Carmichael <wisernet100_at_yahoo.com> wrote:
> > sigh. I need to find time to read ALL the docs.
> > Yeah, that'll happen.
> > If I can find a parallel universe where time runs at
> > a different rate.
> >
> > Thanks, I'll test this out as well.
> >
> >
> > --- Arup Nanda <arupnanda_at_hotmail.com> wrote:
> > > In 9.2, you can keep the index by using the KEEP
> > INDEX key words.
> > >
> > > ALTER TABLE XXX DROP CONSTRAINT PK_XXX KEEP INDEX
> > >
> > > This will keep the index but drop the constraint.
> > Talk about having
> > > your
> > > cake and eating it too...;)
> > >
> > > HTH
> > >
> > > Arup
> > > ----- Original Message -----
> > > To: "Multiple recipients of list ORACLE-L"
> > <ORACLE-L_at_fatcity.com>
> > > Sent: Friday, December 27, 2002 4:39 PM
> > >
> > >
> > > > it'll have to wait until Monday, I'm not at work
> > until then. I'll
> > > try
> > > > it with a non-unique then
> > > >
> > > > Hey, if it works, it saves me tons of time, I
> > learn something new
> > > and I
> > > > had fun developing the single SQL statement to
> > rebuild the
> > > constraint
> > > > and index. Win-win
> > > >
> > > >
> > > > Rachel
> > > >
> > > > --- Denny Koovakattu <groups_at_koovakattu.com>
> > wrote:
> > > > >
> > > > >
> > > > > I don't have access to 9.2.0.1 right now.
> > But can you try
> > > creating
> > > > > a non-
> > > > > unique index instead of the unique index. If
> > you create a unique
> > > > > index, it gets
> > > > > dropped. That's the behavior on 8.1.x also.
> > But if it's a
> > > non-unique
> > > > > index, it
> > > > > shouldn't get dropped.
> > > > >
> > > > > Regards,
> > > > > Denny
> > > > >
> > > > > Quoting Rachel Carmichael
> > <wisernet100_at_yahoo.com>:
> > > > >
> > > > > > 9.2.0.1 Solaris, and yes, it does drop it
> > > > > >
> > > > > > I created a unique index in the primary key
> > columns
> > > > > > I created the primary key constraint without
> > specifying an
> > > index
> > > > > > I checked that the index existed, it did
> > > > > > I dropped the primary key constraint
> > > > > > I checked that the index existed, it didn't
> > > > > >
> > > > > > try it.... I tried various combinations
> > before posting this
> > > note
> > > > > >
> > > > > >
> > > > > > --- Denny Koovakattu <groups_at_koovakattu.com>
> > wrote:
> > > > > > >
> > > > > > >
> > > > > > > If you build a separate index to enforce
> > the primary key,
> > > > > Oracle
> > > > > > > shouldn't
> > > > > > > drop it when you disable or drop the
> > primary key.
> > > > > > >
> > > > > > > Regards,
> > > > > > > Denny
> > > > > > >
> > > > > > > Quoting Rachel Carmichael
> > <wisernet100_at_yahoo.com>:
> > > > > > >
> > > > > > > > Here's a reason:
> > > > > > > >
> > > > > > > > have you ever tried to find the three
> > duplicate rows in a
> > > 12
> > > > > > > million
> > > > > > > > row table without using the primary key
> > constraint? I've
> > > had to
> > > > > > > > disable
> > > > > > > > or drop the constraint in order to use
> > the exceptions
> > > table.
> > > > > Once
> > > > > > I
> > > > > > > do
> > > > > > > > that, even if I've built a separate
> > index that enforces the
> > > > > > primary
> > > > > > > > key
> > > > > > > > constraint, Oracle drops the index. So I
> > HAVE to rebuild
> > > it. If
> > > > > I
> > > > > > > > allow
> > > > > > > > the index to be rebuilt when I re-enable
> > the primary key
> > > > > > > constraint,
> > > > > > > > it
> > > > > > > > builds it in the default tablespace of
> > the table owner, not
> > > > > where
> > > > > > I
> > > > > > > > want it.
> > > > > > > >
> > > > > > > > if anyone has a better way to fix this
> > problem, I'm more
> > > than
> > > > > > happy
> > > > > > > to
> > > > > > > > hear it! It's a data warehouse and the
> > third party app has
> > > a
> > > > > bug
> > > > > > we
> > > > > > > > can't find and on occasion sqlloads (via
> > direct path)
> > > duplicate
> > > > > > > rows
> > > > > > > >
> > > > > > > > Rachel
> > > > > > > >
> > > > > > > > --- Jared Still <jkstill_at_cybcon.com>
> > wrote:
> > > > > > > > >
> > > > > > > > > Though I have published a script for
> > determining indexes
> > > that
> > > > > > > > > need to be rebuilt, and then
> > rebuilding them, I have to
> > > say
> > > > > > that
> > > > > > > > > this is almost never necessary.
> > > > > > > > >
> > > > > > > > > Why are you rebuilding indexes? About
> > the only reason
> > > for
> > > > > ever
> > > > > > > > > doing so is that the BLEVEL >= 5.
> > > > > > > > >
> > > > > > > > > goto asktom.oracle.com, and do a
> > search on 'index
> > > rebuild'.
> > > > > > > > >
> > > > > > > > > Currently, the third article may be of
> > interest.
> > > > > > > > >
> > > > > > > > > Jared
> > > > > > > > >
> > > > > > > > > On Thursday 26 December 2002 12:24,
> > Richard Huntley
> > > wrote:
> > > > > > > > > > Anyone have any useful scripts for
> > doing this?
> > > > > > > > > >
> > > > > > > > > > TIA,
> > > > > > > > > > Rich
> > > > > > > > >
> > > > > > > > >
> > ----------------------------------------
> > > > > > > > > Content-Type: text/html;
> > charset="iso-8859-1";
> > > > > name="Attachment:
> > > > > > > 1"
> > > > > > > > > Content-Transfer-Encoding: 7bit
> > > > > > > > > Content-Description:
> > > > > > > > >
> > ----------------------------------------
> > > > > > > > > --
> > > > > > > > > Please see the official ORACLE-L FAQ:
> > > http://www.orafaq.net
> > > > > > > > > --
> > > > > > > > > Author: Jared Still
> > > > > > > > > INET: jkstill_at_cybcon.com
> > > > > > > > >
> > > > > > > > > Fat City Network Services --
> > 858-538-5051
> > > > > > > http://www.fatcity.com
> > > > > > > > > San Diego, California --
> > Mailing list and web
> > > hosting
> > > > > > > > services
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > >
> >
> ---------------------------------------------------------------------
> > > > > > > > > To REMOVE yourself from this mailing
> > list, send an E-Mail
> > > > > > message
> > > > > > > > > to: ListGuru_at_fatcity.com (note EXACT
> > spelling of
> > > 'ListGuru')
> > > > > and
> > > > > > > in
> > > > > > > > > the message BODY, include a line
> > containing: UNSUB
> > > ORACLE-L
> > > > > > > > > (or the name of mailing list you want
> > to be removed
> > > from).
> > > > > You
> > > > > > > may
> > > > > > > > > also send the HELP command for other
> > information (like
> > > > > > > subscribing).
> > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > __________________________________________________
> > > > > > > > Do you Yahoo!?
> > > > > > > > Yahoo! Mail Plus - Powerful. Affordable.
> > Sign up now.
> > > > > > > > http://mailplus.yahoo.com
> > > > > > > > --
> > > > > > > > Please see the official ORACLE-L FAQ:
> > http://www.orafaq.net
> > > > > > > > --
> > > > > > > > Author: Rachel Carmichael
> > > > > > > > INET: wisernet100_at_yahoo.com
> > > > > > > >
> > > > > > > > Fat City Network Services --
> > 858-538-5051
> > > > > > http://www.fatcity.com
> > > > > > > > San Diego, California -- Mailing
> > list and web
> > > hosting
> > > > > > > services
> > > > > > > >
> > >
> > === message truncated ===
> >
> >
> > __________________________________________________
> > Do you Yahoo!?
> > Yahoo! Mail Plus - Powerful. Affordable. Sign up
> > now.
> > http://mailplus.yahoo.com
> > --
> > Please see the official ORACLE-L FAQ:
> > http://www.orafaq.net
> > --
> > Author: Rachel Carmichael
> > INET: wisernet100_at_yahoo.com
> >
> > Fat City Network Services -- 858-538-5051
> > http://www.fatcity.com
> > San Diego, California -- Mailing list and web
> > hosting services
> >
> ---------------------------------------------------------------------
> > To REMOVE yourself from this mailing list, send an
> > E-Mail message
> > to: ListGuru_at_fatcity.com (note EXACT spelling of
> > 'ListGuru') and in
> > the message BODY, include a line containing: UNSUB
> > ORACLE-L
> > (or the name of mailing list you want to be removed
> > from). You may
> > also send the HELP command for other information
> > (like subscribing).
> >
>
> =====
> Connor McDonald
> http://www.oracledba.co.uk
> http://www.oaktable.net
>
> "GIVE a man a fish and he will eat for a day. But TEACH him how to fish,
and...he will sit in a boat and drink beer all day"
>
> __________________________________________________
> Do You Yahoo!?
> Everything you'll ever need on one web page
> from News and Sport to Email and Music Charts
> http://uk.my.yahoo.com
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: =?iso-8859-1?q?Connor=20McDonald?=
> INET: hamcdc_at_yahoo.co.uk
>
> Fat City Network Services -- 858-538-5051 http://www.fatcity.com
> San Diego, California -- Mailing list and web hosting services
> ---------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> the message BODY, include a line containing: UNSUB ORACLE-L
> (or the name of mailing list you want to be removed from). You may
> also send the HELP command for other information (like subscribing).
>

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Arup Nanda
  INET: arupnanda_at_hotmail.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).