In the within of the bases of they give to you, has consolidated in the
years a plan methodology that has given test to satisfy requirement that a methodology for bases of
they give to you must guarantee:
- the name and address regarding the applications and to the systems in game (and therefore the
possibility of I use independently from the problem to the study and the instruments to disposition); it is an essential
requirement for the planning of a database to use of the Virtual Warehouse, that it must be used in various Industrial Districts;
- the quality of the product in terms of correctness, thoroughness and efficiency regarding the employed resources;
- the use facility is of the strategies is of the reference models.
We have three is made of planning:
- Conceptual planning. Its scope is that one to represent the detailed lists informs them of the truth of interest in terms
of a formal description and completes, but independent from the represent criteria it uses you in the
systems of management of the bases of give to you. The product of this phase comes called conceptual outline and ago reference
to a conceptual model of gives to you. In this phase it is concentrated to us on the informative aspect of the base of give to
you.
- Logical planning. It consists in the translation of the conceptual outline, in the model of represent of give
to you adopted from the system of management of base of give to disposition. The product of this phase is the logical outline
of the base of gives to you and ago reference to a logical model of gives to you. It is still independent from physical details.
In this phase a quality control of the product is carried out also, with the normalization.
- Physical planning.
Such model depends on the specific system of management bases of gives to you chosen and it is based on the criteria of physical
organization of give to you in that system.
Hour the various ones will be acquired knowledge are made of planning of bases
of give to you, adapted to insert the Virtual Warehouse.
THE CONCEPTUAL PLANNING: THE MODEL ENTITY-RELATIONS
In this type of planning three fundamental figures of represent are used:
- Entity; they represent classes of objects (made, things, persons, as an example) that they have common property and
"independent" existence to the ends of the interest application. An occurrence of an entity is not a value that identifies
an object, but the same object.
- Relations; they represent the logical ties, meant you for the application of interest,
between two or more entity.
- Attributes; they constitute the elementary property of entity or relations that are of
interest to the ends of the application.
