Monday, December 07, 2009

A fairly unique opportunity...

CJ Date will be giving a seminar in Dallas Texas next month. I wish I could get to it myself - but I'm already fully committed that week.

Maybe we can get the answer to using NULLs. Or at least some more input :)


Blogger Gordon said....

While I too cannor atttend this seminar, I do have a copy of "SQL and Relational Theory: How to Write Accurate SQL Code" wrapped and sitting under my Chtistmas tree for me. (I bought it for myself.)
I would lookup the sections on using NULLs right now but I'm certainly not allowed to open my Christmas present early...

Mon Dec 07, 12:46:00 PM EST  

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Sun Dec 13, 10:45:00 AM EST  

Anonymous Anonymous said....

I was fortunate enough to take a class taught by him. We were staying in the same hotel and hit the same restaurant for dinner one evening. I got to spend several uninteruppted hours discussing NULLOLOGY and the theory on what a NULL really means in a database and column.

Wed Jan 13, 03:34:00 PM EST  

Anonymous Another Anonymous said....


tell us more.
What did you learn about NULLOLOGY ?

Thu Jan 14, 04:55:00 AM EST  

Anonymous Anonymous said....

Hello! You were in Russia?

Wed Feb 03, 05:13:00 AM EST  

Blogger Thomas Kyte said....

will be in russia - week of feb 22nd 2010. Moscow.

Wed Feb 03, 08:34:00 AM EST  

Blogger JorgeLarre said....

As per his book "SQL and Relational Theory" (Publisher: O'Reilly Media, Inc., Pub. Date: January 23, 2009,
Print ISBN-13: 978-0-596-52306-0), C.J. Date is quite firm about his position on NULLS:
From Chapter 1, 1.4.2 Integrity Features:
As for the entity integrity rule, well, here I have a problem. The fact is, I reject the concept of "nulls" entirely; that is, it is my strong opinion that nulls have no place in the relational model. (Codd thought otherwise, obviously, but I have strong reasons for taking the position I do.) In order to explain the entity integrity rule, therefore, I need to suspend disbelief, as it were (at least for a few moments). Which I'll now proceed to do…but please understand that I'll be revisiting the whole issue of nulls in Chapters Chapter 3 and Chapter 4.

Mon Feb 15, 05:08:00 PM EST  

Blogger Thomas Kyte said....


That might be an opinion of his, however, the fact remains, they are there. They exist. They cannot be ignored. Even if you choose to implement (typically very poorly performing) schemas that forbid their use - they exist and will have to be dealt with.

Me, I prefer to understand how they are implemented (different from how we THINK they should be - that is true of most things) and use them safely given the context.

Tue Feb 16, 08:58:00 AM EST  

Blogger JorgeLarre said....


Yes, my opinion is very close to yours, in that respect.

I just pointed to Date's book because in it he explains quite clearly his position about NULLS (of course, it is not the first time he does so). And since it is one of his most recent books, I think we can consider it as his current position on the matter (and it seemed relevant to the original post).

As per NULLS, I do not consider them a key element of the relational data model, in the sense that my understanding of its foundations is not affected by whether NULLS are allowed or not. I know that this is a controversial point, but it is too high level for me to grasp all the arguments of the discussion. Without NULLS, my work with relational databases would have been much more difficult.

Tue Feb 16, 12:56:00 PM EST  

Anonymous Anonymous said....

I detest nulls! I have done so ever since I was chased by one across a field.

Oh. Sorry. I meant bulls.

Fri Feb 19, 12:05:00 PM EST  

Blogger Esteban said....

Good Night Mr. Tom Kyte
He writes Est Valderrama José Esteban Villegas National University of Callao, Peru.
The reason why I contact you is to invite you to our XVIII CONGRESS OF SYSTEMS ENGINEERING STUDENTS AND COMPUTERS - CONEISC UNAC 2010 to be held on 9 to 14 August this, we look forward to having its presence as a leading specialist database and Oracle applications.

Hoping to have your presence and make the necessary arrangements to formalize its exposure in our great event, we may talk in agradeceriamos email address: esteban.villegas @

No other issue in particular, waiting your quick response, I say goodbye


Thu Mar 04, 11:47:00 PM EST  

Blogger Thomas Kyte said....


sorry, I was actually just recently in Peru for technical seminars and am already booked during the time of your seminar.

Fri Mar 05, 05:32:00 AM EST  

Anonymous Anonymous said....

Hello Tom,
What is your take on the SAYNOTOSQL movement?

Personally I find it intriguing and I wonder if there's a point they are trying to make.

I would like to know your thoughts.

Tue Mar 16, 11:26:00 AM EDT  

Anonymous gih said....

Ok, thanks for that information.

Thu Apr 01, 07:28:00 AM EDT  

Anonymous Anonymous said....

why do you stop writing in your blog Mr. Tom?

Thu Apr 01, 12:49:00 PM EDT  

Anonymous Травиан said....

We were staying in the same hotel and hit the same

Sun Apr 11, 12:42:00 PM EDT  


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