Re: design question
Date: Sun, 07 Sep 2008 11:20:00 -0700
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.
CREATE TABLE t1 (
attr001 VARCHAR2(5), attr002 VARCHAR2(5), attr003 VARCHAR2(5), ... VARCHAR2(5), attr100 VARCHAR2(5)); CREATE TABLE t2 ( rid NUMBER,
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 damorgan_at_x.washington.edu (replace x with u to respond) Puget Sound Oracle Users Group www.psoug.orgReceived on Sun Sep 07 2008 - 13:20:00 CDT