The Database Design Resource Center

But null IS a value!

by Steve Cosner
(Fresno, California, USA)

In your very first example: "Notice the column AVAILABLE: for account_no 30 it holds a NULL value. How could that be?"

As soon as you say it "holds a null value" or even if you say "it is null", it is NO LONGER an unknown, or undefined, or whatever you want to call it. As soon as you create a row in a table with a null column value, you (and the computer) have identified it ...and given it a value. If you identify it as anything, you have given it value. And therefore it has meaning.

It is pure insanity to fool ourselves into thinking it is beneficial to treat nulls as something different when it comes to database logic.

I've been writing code for over 30 years, and handle NVL functions confidently all the time. But I have YET to see any example where handling a null "non-value" was best treated separately from other known values.

It is just stupid that (null = null) is not true, or that ("xyz' not = null) is not false!

Treating null differently from known values within a database is an evil joke played on computing professionals.

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