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Re: 3 value logic. Why is SQL so special?

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Tue, 19 Sep 2006 05:05:51 GMT
Message-ID: <PUKPg.22753$9u.271044_at_ursa-nb00s0.nbnet.nb.ca> 






Chris Lim wrote:



> Bob Badour wrote:


> 

>>SQL never will, which is ultimately why SQL is irrelevant.




> 

> Then I guess your argument does not apply to databases using SQL (even


> though this is comp.databases.theory, I mistakenly thought you were

> talking about the real world, i.e. SQL).

> 

> I don't know why you have dealt with so many people who have trouble

> with NULLs - to me this is a beginner's problem that is dealt with very

> easily. 




I can only conclude that you are either a neophyte or a dilettante. The 
problems with NULL are legion and very well documented elsewhere.



NULL confuses reasonably intelligent people because it breaks important 
identities those people have been conditioned to expect such as:



SUM(A) + SUM(B) = SUM(A+B)



select sum(a) from atable;
select sum(b) from atable;
select sum(a+b) from atable;





In the presense of NULL, those queries violate the identity above.
Received on Tue Sep 19 2006 - 07:05:51 CEST












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