Re: design question

From: DA Morgan <>
Date: Sun, 07 Sep 2008 11:20:00 -0700
Message-ID: <>

Chris Seidel wrote:
> DA Morgan wrote:

>> Most things have NULL columns ... what's the issue?

> A table with lets say 100 columns and 90 % NULLs in each row is no problem
> for the database performance and storage?

You are thinking horizontally when you should be thinking vertically.

Consider the following two tables.


attr001 VARCHAR2(5),
attr002 VARCHAR2(5),
attr003 VARCHAR2(5),
...     VARCHAR2(5),
attr100 VARCHAR2(5));

rid     NUMBER,

attrnum NUMBER(3),
attrval VARCHAR2(5));

One is well designed ... the other a nightmare. And has nothing to do the question of NULLs. Reconsider the way you are approaching the problem.

And I am in complete agreement with hpuxrac. VARCHAR2(4000) does not belong in any database for the purpose you seem to be intending.

Daniel A. Morgan
Oracle Ace Director & Instructor
University of Washington (replace x with u to respond)
Puget Sound Oracle Users Group
Received on Sun Sep 07 2008 - 13:20:00 CDT

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