Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

paul c schrieb:
> Alexandr Savinov wrote:
>

>> paul c schrieb:
>>
>>> Alexandr Savinov wrote:
>>>
>>>>  
>>>> ... If something disappears, if something is deleted then acutally 
>>>> we get null.
>>>
>>>
>>>
>>>
>>> i think we get 'false', according to the CWA.
>>
>>
>>
>> Actually it is one and the same, i.e., null, false, empty set ...

Why do you say that we do not need nulls - may be we do not need false :-)

But actually you are absolutely right - we do not need so many terms for designating the same things. Unfortunately, it is a historical and political issue. Different branches of science are born and then exist independently starting from some fundamental assumptions and only later people start recognizing that they expressed in other terms what has existed before or in parallel. Political aspect is that different scientific gangs are trying to establish and retain their priority and independence so they are against unification of terms. The terms become their flag and they fight for the possession of the flag as their symbol. Different terms of course play also very positive role because they actually reflect different priorities in the theory and its subtle features.

For example, what is the difference between row, record, tuple and object? They designate one and the same but in different contexts in order to emphasize different aspects of the theory where they are used.

-- 
alex
http://conceptoriented.com