5.4.2. From DCD to Data Logical
Relational Data Model (DLRM) rules
As mentioned above, the passage of the DCM to DLRM is purely
mechanical, simply meet and set some rules.
5.4.2.1. Entity and table
Each entity becomes a table and therefore, the identifier
becomes the primary key, the properties of the entity become the table
attributes.
Figure 6: the table
Article
5.4.2.2. Binary relation with cardinalities (X,1) - (X,n),
X=0 or X=1
The entity type cardinality 1.1 or 0.1 absorbs the identifier
of the strongest entity (0, n or 1, n). This identifier is then called the
foreign key.
5.4.2.3. Binary relation with the cardinalities (X,n) -
(X,n), X=0 or X=1
Where n is the maximum cardinality of both sides of the
relationship it becomes entity and absorbs identifiers each related entity.
Without enough IDs are the new key of the entity. This new key is formed by the
concatenation of the foreign key related entities.
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