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RE: Counterquestion - is Oracle a He or a She - or an It or a hermaphrodite

From: Billy Verreynne (JW) <VerreyB_at_telkom.co.za>
Date: Mon, 1 Aug 2005 08:23:08 +0200
Message-ID: <445F36B0271AE1419CEE0B9589044B433747B6@TYGRRA01-XCS00.telkom.co.za>

Mark W. Farnham wrote:

> So I'm thinkin' Oracle is a high flyin' she, which partly
> explains why she thinks a zero length string is a null
> value but simultaneously understands that a numeric
> zero is not a null.

Null is not a value. Just like infinity is not a value. Null is a state. Or is it in this case a non-existant state? ;-)

Which is why [NULL != NULL] as mathematical operations are not valid - state operands are required. Infinity makes this easier to grasp e.g. [INFINTY != INIFINTY] as the INFINITY "value" is always be greater than the INIFINITY+1 "value". Thus it cannot ever be a value. It is a state. Ditto for NULL.

A string that is empty is in Oracle terms a non-existant string. E.g. with a trailing NULL string column in a table, *nothing* is stored. NULL simply means that there is no value for that column or variable.

Now you can argue that there's a difference between an empty string and a null string.. and I will simply point out that this difference is the same as the mathematical difference between (INFINITY+1) and INFINITY. I.e. an empty string has no value. Do not think of that "emptiness" as a valid string value. Sheez, how can it when it does not contain a single character?

The way that Oracle deals with nulls has always made sense to me, especially from an OO programming viewpoint. So I honestly do not see what the issue is about Oracle and NULLs that seems to be an issue for others.

--
Billy

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Received on Mon Aug 01 2005 - 01:25:39 CDT

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