Re: NOT NULL

From: Rajesh Pillai <pillair_at_il.us.swissbank.com>
Date: 1997/03/12
Message-ID: <332717DC.1FC6@il.us.swissbank.com>#1/1

Minh Giang wrote:
>
> Hi,
> How much performance degradation to a table with all fields defined with
> NOT NULL compare to a table with one or two fields defined with NOT NULL?
>
> TIA
> --
> Minh Giang
> mpg_at_fast.net

I am not going to guess at the perf. degradation when columns are declared as nullable... but from a sybase point of view there are some consequences.. Nullable columns are treated as variable length columns.. hence they incur additional space overhead associated with variable length columns..

Also there is a perf. penalty when nullable columns are joined with non nullable columns for eg. char null with char not null, since a conversion is involved..

Hope this helps,

Rajesh Pillai
Perot Systems Corp. Received on Wed Mar 12 1997 - 00:00:00 CST