Everything should be relational!

by Simon St. Laurent

Related link: http://www.firstsql.com/dbdebunk/xmldev1.htm



Fabian Pascal seems to think that the relational model should rule data management, period, and that those of us who disagree just don't understand. I hope I don't sound this cranky when I'm pushing XML for data management.



If the relational model is so fantastic, why does it seem that no one has fully implemented it?



Do tables always trump hierarchy?


12 Comments

anonymous2
2003-02-03 14:23:24
dbdebunk strikes back
This weblog entry is now featured as the "Quote of the Week" at www.dbdebunk.com. (Quotes of the week are meant to represent outstanding examples of ignorance about relational matters).


It does seem a weak argument, like saying in the time of the Wright Brothers "If man-made flying machines are so good, why hasn't anyone made one?"

simonstl
2003-02-04 13:03:01
more ways to fly than relations
anonymous writes:
---------------------
It does seem a weak argument, like saying in the time of the Wright Brothers "If man-made flying machines are so good, why hasn't anyone made one?"
---------------------


It might be a weak argument, except that machines for flying through the air have been available for decades now. They might not be precisely the design that certain folks want, but mysteriously, they do get off the ground, move to the desired location, and land - all on a surprisingly regular basis.


If Fabian Pascal's rantings about markup weren't so astounding, I might be depressed about being featured in a place that is "meant to represent outstanding examples of ignorance about relational matters". As it is, I'll just laugh, and re-read the book that first taught me about how to use relational databases - _SQL and Relational Basics_, by Fabian Pascal. (M&T Books, 1991.)


Good stuff, Wright brothers or no - but not the whole universe.

anonymous2
2003-02-20 20:36:17
Not just ignorance, but poor reasoning too
The relational model is nothing but the application of logic -- specifically, predicate logic -- to database management. Those who trumpet the existence of "other ways to fly"-- what is it that they offer as a replacement for logic? And if they offer none, can they really claim with a straight face that database management should NOT be based on logic?


I also dare them to produce any evidence that relational proponents say anything about "the world". We are referring only to database management, which IS the domain of logic, whether ignorami realize and/or appreciate it, or not.


So it is at themselves that they are really laughing, but then ignorance is bliss, ain't it?


Fabian Pascal
editor and publisher,
database debunkings
www.dbdebunk.com


simonstl
2003-02-21 07:40:25
Relational model has no monopoly on logic
I have no problem with the relational model or with people who use it. I find claims that the relational model is the the only appropriate logic for database management and that anyone who disagrees with this is part of "the ignorami" to both wrong and deeply obnoxious.


anonymous2
2003-04-20 22:53:02
Relational model has no monopoly on logic
I did not expect any better "answer" than this, which proves beautifully what happens in the absence of logic.


1. To repeat: if the relational model is NOT the only appropriate logic for db mgmt, then WHAT OTHER LOGIC IS? And WHY EXACTLY is it better than the relational model? Unless you can specify that, you are grinding water.


2. It's not disagreement that makes one ignoramus, but disagreement without any basis. Your argument is simply meaningless -- and it's ignorance that prevents you from seeing that.


Fabian Pascal
Editor & Publisher
Database Debunkings

anonymous2
2003-04-20 22:57:01
more ways to fly than relations
What is astounding is that you find my "rantings about markup tags astounding". What exactly did you find astounding? Or should we expect things to be true only because you declare them so?


Fabian Pascal
Editor& Publisher
DATABASE DEBUNKINGS

anonymous2
2003-04-21 07:23:48
Sorry, Mr. Pascal
You know a lot about relational databases, and I'm happy to have learned about them from your writings, but you seem utterly incapable of accepting that there might be information for which relational databases are not an ideal storage mechanism or logic which exists outside of the relational calculus.


Fire and brimstone ravings about ignorami, grinding water, and the dire need for relational logic do absolutely nothing for me. It's like you're screaming that newspapers need to be like television, or that movies and radio should be the same. There's a whole set of information media that can exist separately from relational systems, and you'd do well to acknowledge them.


Your expertise in relational systems is impressive. Your consistent refusal to see the computing world outside of that perspective is ridiculous.

simonstl
2003-04-21 07:24:40
claiming that one
Yep, that was me, not 'anonymous'.
anonymous2
2003-04-28 05:36:02
Sorry, Mr. Pascal
You should be sorry -- because making statements without supporting them is meaningless.


1. The relational model has NOTHING to do do with storage -- that is precisely why it was invented.
You suffer from the very common logical-physical confusion.


2. WHAT other logic -- precisely, please! -- is there that is applicable to database management? Can you specify another theoretical foundation on which db mgmt can be founded that is equivalent or better to predicate logic and set theory?


3. Of course it does not do anything for you and I don't expect it to -- that's what ignoramus means. It is THAT which is ridiculous.


4. And you ARE grinding water whether you realize it or not. Until and unless you stop declaring and start PROVING, that is precisely what you are doing.

simonstl
2003-04-28 06:06:14
Dear Sir:
You appear not to recognize that there are domains where the relational model does not fit particularly well. The relational model (I will not grant you a monopoly on set theory, which also underlies XML work like RELAX NG) works well with data which has been carefully structured to fit its requirements, but tends to collapse when fed data that comes from less-structured sources.


I have no complaints about the relational model's logic when it is applied to data for which it is appropriate. I find the relational model useless at best for dealing with the kinds of messy information - frequently documents, but sometimes data that cannot be forced to fit in tables without loss - that I find most interesting.


If I may quote from SQL and Relational Basics, by Fabian Pascal (M&T Books 1990):


"Codd devised a relational algebra by adjusting set theory to certain types of sets called relations. In the same way in which arithmetic manipulates numbers to create other numbers, relational algebra manipulates relations to create other relations. At a simplfied level, relations resemble unordered tables, namely tables whose order of columns and rows can be shuffled at will without any change in their meaning....Codd's choice of relations was caused precisely by the ability to represent them as tables.... They can - and do - handle most of the data types we usually deal with." (38)


I think it's fairly clear that I spend most of my time outside of what you described as "most of the data types we usually deal with". If you'd care to design a non-tabular relational model that can keep up with a world that fits poorly in "Disciplined Tables", you're quite welcome to do so.


As for me, I'll just be happy that I have a choice of methodologies which are useful for different situations, as well as tools for processing, storage, and presentation which are appropriate for different needs.


I suspect that this doesn't constitute proof for you, but I'm not at all interested in your style of proof. Your approach has done wonderful things for some aspects of my work, but I have no plans to let it hobble the rest. If that's "grinding water", perhaps we have different conceptions of water.

anonymous2
2003-04-28 06:26:54
Dear Sir:
In several instances I asked you to PROVE PRECISELY certain points which you were declaring without grounding. Instead, you either repeated the same declarations, or made additional ones.


That is precisely what I expected, because you CAN'T ground your claims in a persuasive manner, in large part because you don't know enough to do so. "Works well" is not a substitute to providing an equivalent theory to the relational model. What exactly is the theory or logic behind XML, if any?


Anyway, I am no longer responding here. I will post a thorough assessment of your claims at DATABASE DEBUNKINGS.


Fabian Pascal
Editor and Publisher,
DATABASE DEBUNKINGS
www.dbdebunk.com

anonymous2
2003-08-26 11:43:47
More!
This debate is lacking...erm...debate.


Mr Pascal is precise in his questions, yet they remain unanswered. Does anyone else find this as wierd as a bucket of hair - and far less satisfying?


PhilK