La logique informatique
(selon les travaux de J.D WARNIER)
L.C.S organizing data in a computer system
Study of Operational Logical Files
The purpose of this last stage of data organization of a computer system is to master the redundancy of data that can be found within the files that we have defined in our system, and from there, discover all Logical-Primary Subfiles, that is, all the mathematically perfect and unique data sets in the system.
it is by performing the logical meeting of these subfiles that we will obtain the operational logic files (F.L.O in french) of our system.
Having done the study of the sets without taking into account any redundancy in the data contained, has greatly facilitated the task, but now we must check if data redundancies exist, and decide what we let's do it.
In absolute terms, this is not important work, because as you can imagine, this study will only cover sets of the same nature, that is, there can be potential redundancies between FLP for third parties , or objects exchanged, which greatly limits the scope of the study.
That being the case, before addressing this study concerning the Logical Operational Files, I would like to make an extremely important remark,
Not to be confused : The physical files created by the service computer scientist, and the Operational Logical Files which are only the result of a pure mathematical study, and which have absolutely nothing to do with physical files !
I will give you two examples that perfectly illustrate the creation of physical files from a mathematical reflection that any computer scientist used of course :
1 °) There is a Bijective application between two files,
2 °) there is an injective application of the whole of the recordings of a file in all the recordings of another file,
( In both cases the logical files are disjoint )
Let us take the case N ° 1 for example, here are two disjoint sets whose correspondence is a bijective application :
In this case, the two files can be combined into one
Physical File
This would be the case, for example, of the F.L.P concerning the staff considered as client of the company, concerning social benefits and the F.L.P concerning the personnel considered to be the supplier of his work.
Take case N° 2 for example, here are two disjoint sets whose correspondence is an injective application:
In this case, the two files can be combined into one
Physical File.
This would apply, for example, to the FLP (A) relating to the insured persons of an insurance company and the FLP (B) relating to their spouses (assuming of course that they can only have one and A single spouse). It should be noted in the latter case that we will obtain blank or zero data fields to notify the absence of a spouse !.
Here we have defined physical files and not Logical Operational Files
These examples show the essential difference that exists between the computer file definition performed by the computer scientist using his nose and his common sense, and the notion of Logical Operational File resulting solely from the mathematical study of data intersection between several sets of data (FLP (Logical Primary Files).
If you have the courage to follow me, let's tackle the study of the double intersection Recordings and data fields of FLP, which I think is perhaps the most important part of the data study of a system, because it goes generate a whole new approach to tomorrow's DBMS.
work on the double intersection "records and data fields" ----->