The project Dated
Modeling of the data the diagram star

  Modeling of the data

Bases are conceived according to the entity-relation model (from which in particular the MERISE Method of H. is resulting, A. , R. ).

To avoid the tragedies problems of design (redundancy, hazardous indexing…) there exist techniques of “standardization” to guide the process of design. These techniques of standardization are called the “normal” forms.
For memory, there exist ain normal forms called: 1FN, 2FN, 3FN guaranteeing atomization entity, properties, relation and of the established relational diagram.
does not have the same requirements at all nor the same use Dated.
The design patterns are completely different. They by definition. One retains two main: the star diagram (Star Diagram) and the diagram in flake ( Diagram).

The data model out of star

The data model out of star owes its name with its form. This design pattern privileges the approach user, the guideline trade.
The table of reference contains the facts. The facts or measurements are the statistical data (of the results type by sector). The satellite tables correspond to dimensions. They are the axes of analysis of the users.
Thus, as of the design, the basis is directed by taking account of the types of search of the users.

The data model “in flake” is an alternative of the star model.

Some resource complementary