Re: c.d.theory glossary - NULL

From: Alfredo Novoa <>
Date: Wed, 28 Apr 2004 15:31:42 GMT
Message-ID: <>

On Wed, 28 Apr 2004 08:45:38 -0400, "Laconic2" <> wrote:

>"Alfredo Novoa" <> wrote in message
>> The zero byte is at the physical level and the null at the logical
>> level.
>> The bit vector is at the physical level and the SQL nulls at the
>> logical level.
>In this case, it's a distinction without a difference.

There is a fundamental difference, the bit vector is hidden to the users and it could be changed by any other physical representation without affecting the logical model. That's data independence.

Bit vectors are bit vectors, not nulls

Regards Received on Wed Apr 28 2004 - 17:31:42 CEST

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