Re: NULL versus NOT NULL usage

From: R.Schierbeek <bytelife_at_worldonline.nl>
Date: 1998/06/01
Message-ID: <6kuiqr$kq5$1_at_news.worldonline.nl>#1/1

RABK heeft wrote in bericht <01bd8ced$70ff01a0$4b36a8c0_at_ctmnnt022b>...
>I am researching the benefits of NOT NULL versus NULL datatypes and am
>interested in the viewpoints of the exp dba, client developers.
>Describe the benefits of using a table that has NOT NULL versus a NULL data
type.

Real speed benefits in Oracle databases: Null values are not indexed, even if the field has an index on it.

>Do NULLS in general cause more heartache for client developers? Why?

Yes, performance problems for example

>Do NOT NULL save enormous amounts of space.

Minimal savings, really.

>What issues arise from querying fields that have NULLS in them?

Performance, performance, and it is hard to "see" the nulls.

In short: key fields and index flied are better off NOT null. Regards, roelof

---

Roelof Schierbeek, DBA
Bytelife BV
The Hague, Holland
email: bytelife AT worldonline.nl
http://home.worldonline.nl/~bytelife Received on Mon Jun 01 1998 - 00:00:00 CEST