I think it is necessary to clearly specify the model and exactly what people are doing when they use the model. Given that this is a very important and broad topic, I'll simplify this, in order to get a better explanation what the model is. Unfortunately on this topic has no literature.
When a man does some complex projects in the real world he uses the model. Models are used extensively in architecture, engineering, databases etc.. Schematically, this can be represented as the following triplet:
(*) Man Model RealWorldProject
Here, the model could be anything. But the most important and most powerful type models are mathematical models. For example, the model may be a partial differential equation that describes some of the technical-physical project. The model can be Boolean algebra that models the design of electronic circuits. Obviously this type of model is pure mathematics, these models are not a technical or special models flavored with mathematics. Many database theorists for many parts of db theory claim that it is math. I also think it is math, in fact I think that's part of the new math that has a great future.
So I think that the Relational Model is pure mathematics, which includes substantial mathematical theories: Propositional Logic, Predicate Logic, Relations, Sets, Formal theory of spoken languages, Semantics …
In the last 50-60 years, the mathematical theory of “semantic models” was developed dramatically. In this area, the most important is the Model Theory. Many famous mathematicians claim that this is the highest achievement in mathematics. The father of semantics is G. Frege and the father of the Model Theory is A. Tarski.
The relational model is a specific semantic model that fully describes how works the following triplet: Man-Model-RealWorldProject.
In this thread I claim: everything that exists in the relational model exists in the works of G. Frege. If you think there is something that belongs to the Relational model and does not belong to the Frege's theory, then you should put it on this topic. Of course, in this case, my statement is not true. Otherwise, my statement is correct.
I've never seen that Codd mentions Frege, that's why I wrote "What Codd did not do that is that he did not say that he copied Gottlob Frege."
However, I think that Codd is very important for theory of database, primarily because he has used Frege's theory as Relational Model, and thus he raised the theory of database to the highest level, that is, on the level of mathematical theory. Codd also has significant results in the field of FDs. I also think his results in Relational Algebra are important, but I've learned on this user group that Tarski has done a lot in this area. I guess you mentioned Tarski in this regard.
Vladimir Odrljin
Received on Fri Sep 06 2013 - 13:22:21 CEST
