La logique informatique
(selon les travaux de J.D WARNIER)
L.C.S organizing data in a computer system
Determine the contents of each Primary Logical File.
First, two categories of data (fields) must be stored in each F.L.P, these are the codes enabling them to be linked.
1°) Any element of a set must be able to be identified uniquely, to do this we must decide the code (meaningful or not) that will allow this identification, and that we will call IDENTIFIER.
2°) In order to establish the relation between an element of a set (FLP) considered as a starting set to an element and only one in the set (FLP) of arrival we must have in the starting set, a code allowing the realization of this correspondence and which we will call CRITERIA OF APPLICATION. This application criterion will be neither more nor less than the identifier of the arrival set.
There are already two fields to be defined in each of the files. (Small example below)
Now let's discover the other data fields of each of our F.L.P.
This step is after the F.L.P's determination, certainly the most important. For if at first sight this may seem simple, you will see that it can prove to be sometimes complex.
In fact, we have on one side the containers (F.L.P) defined perfectly in understanding and on the other (following the L.D.R study) contents (primary data) to be stored in our system.
Easy tell me you, it is enough to make the study of belonging of each primary data with its container!, It is true ! That's what we're going to do.
But ATTENTION, a data field (part of an image on an object of the real world) must be (in pure logic) associated with its object ! And that is where we will sometimes have decisions to make, but fortunately for us, and through the definition in understanding of our F.L.P, we will know what we are doing.