La logique informatique
(selon les travaux de J.D WARNIER)
L.C.O The organization of companies
The data sets of a step :
Before beginning this chapter on the organization of the data of the computer system, I would like to make a few remarks :
If I were to characterize in two words the work on the computer logic of J. D WARNIER, it would undoubtedly be :
Logic of data organization
Indeed, when it comes to the operation of any system, and even more so of a computer system in which the number of elements stored and used is very large, the first thing to do, the principal, the first step, what it is imperative to start, otherwise nothing is possible ...... it is the organization of processed and processing data !
But for this, it is necessary that the laws of organization used are :
Universal and based on exact sciences such as mathematics.
Only then can this science be taught and used by all.
Everyone agrees implicitly on this law :
Any collection of data must be considered as a set in the mathematical sense of the term.
Only one explicitly : J.D WARNIER
When one speaks of a set in the mathematical sense of the term, one must define it in the most precise way possible.
A set is defined in two possible ways :
1°) By understanding i.e by expressing all the characteristics (or properties) that must have every element to belong to the set.
2°) In extension i.e by making an exhaustive list of all the elements of the set.
As far as we are concerned (and I teach nothing to computer scientists !), our concern will be to store elementary data (we shall see later that we will call them "primary" data) in "files", consequently we will have to define our sets by understanding !.
I remember (for having also studied some other "methods" which had the same concern to create collections "coherent" data), to have heard this kind of sentences :
- Similarities or characteristics common to several entities ! ....
- The objects (or entities) that have certain properties in common, are said to belong to a certain type !
- A type is a class of like objects ! ....
How can we understand these sentences, it is complicated and each one can interpret in his own way, all this is not precise, rigorous, even if in the idea the result must be the same, It would have been so much simpler to say :
An element belongs to the set if it possess the properties of the set defined by comprehension.
It's simple! And this does not support any interpretation !.
Well now that everyone agrees ... we will organize the data one step.