Re: Do columns with Null data take up space?

Hi from Paris

wrong.... whenever a varchar2 column is null, only 1 byte is stored -> 0 and if all following columns are varchar2 and null too , then no more informations will be stored, meaning that they are all with no datas....

so the, the trick is to put any possibly null column at the end of a table in order to gain space...

"DA Morgan" <damorgan_at_x.washington.edu> a écrit dans le message de news: 41e554df$1_1_at_127.0.0.1...
> Doug wrote:
>
>> If I create a table with 250 columns, and only fill 8, do the other
>> columns take up space? (My user wants to log tests. There can be as
>> many at 250 tests in a set, but normally only about 8. My user wants
>> one record per set so he can run some third party analytical software
>> against the test results.) Is Oracle 8i smart enough to compress the
>> null values down so they don't take up space if they are unused?
>
> There is nothing to compress. Null is null. There may be one or two byte
> overhead but of bigger concern is a table with 250 columns. That has all
> of the appearance of a very bad design.
> --
> Daniel A. Morgan
> University of Washington
> damorgan_at_x.washington.edu
> (replace 'x' with 'u' to respond)
Received on Wed Jan 12 2005 - 13:26:55 CST