Re: Use of nulls in single character flag fields

ncronin wrote:
>
> Hi
> We have some conflicting desgin views at our site. Some
> people believe use of nulls for flags is fine as you can
> use NVL(...) to convert when retrieving. I believe flags
> should be non-null for clarity, better performance when
> indexed and you don't have to remember to use NVL all the
> time. Also I'm not sure if there is a performance penalty
> from using NVL(...). Any views on this simple matter from
> the database designers of you ??
> Noel (ncronin_at_tcd.ie)
I agree with you if the flag is often used as criteria in a where clause it is better to make it not null. Nvl is a function and a function in a where clause causes a table scan, which you may not always want if you are indexing the flag attribute. Received on Tue Nov 19 1996 - 00:00:00 CET