RE: Question on indexed nullable column

From: <martyn.r.baker_at_uk.pwcglobal.com>
Date: Fri, 12 May 2000 09:50:55 +0100
Message-Id: <10495.105475@fatcity.com>

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Sorry to correct you but if the column contains a null value, it will not be referenced by the index. As mentioned in an earlier posting, use a default value for the nullable column for it to be stored in the index. Martyn

                                                                  
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Please respond to ORACLE-L_at_fatcity.com

To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> cc:
Subject: RE: Question on indexed nullable column

If an index is created on nullable column, it will not create any problem and put the null value at first place of the index. I think if you make any query against that table for null values than it might be fatser.

-----Original Message-----

Sent: Friday, May 12, 2000 3:17 AM
To: Multiple recipients of list ORACLE-L

Hi:

In Oracle database, if I do:

create table T1 (

     C1  number(9) NOT NULL,
     C2  number(9));

create index INDX1 on T1(C1);
create index INDX2 on T1(C2);

Is here a performance penalty, or other problems if an indexed column is nullable (such as C2 here)? If yes, why?

Thanks.

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<binary content removed -- do not send binaries to the list> Received on Fri May 12 2000 - 03:50:55 CDT