La logique informatique
(selon les travaux de J.D WARNIER)
L.D.R The organization of one output requested
We will take a very simple example to illustrate the use of this criterion of subdivision.
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Suppose we wanted to print an address strip to send a newspaper to subscribers. The requested output is the set of address labels (one per subscriber).
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At the first level, one finds an S-E of data present (n times), this is an address label, here is the corresponding hierarchical diagram:
Note : An address label is a subset included in the level immediately above (address label report)
Let us now turn to the contents of a label. Let us assume that each label must indicate the Name, the subscriber, the street, and the city, and that for foreigners the name of the country must appear.
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We can note that :
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The subset "an address label" must be subdivided because it contains a subset present a number of times different from 1, it is the name of country present 0 or 1 times (one will note (0-1).
We will therefore list the data present 1 time in the set "1 Adress label" (Level 2 of the subdivision) and note the subset "country name" present (0-1).
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Here is the corresponding hierarchical diagram:
And as in computer logic we must be perfect, then we still have one thing to do, note the headings present 1 time in the set.
Here is the complete diagram!
