Information Modeling and Relational Databases, 2nd Edition

9.8. Mapping from ORM to UML

The UMLmap procedure in Table 9.3 provides basic guidelines for mapping ORM schemas to UML class diagrams. Selected entity types and value types map to object classes and data types, including attribute domains when associations are replaced by attributes. We now illustrate this procedure. As a preparatory move, step 1 binarizes any sets of exclusive binaries, as shown in Figure 9.55.

Table 9.3. UMLmap procedure.

Step	Action
1	Binarize any sets of exclusive unaries
2	Model selected object types as classes, and map a selection of their n: 1 and 1:1 associations as attributes. To store facts about a value type, make it a class
3	Map remaining unary fact types to Boolean attributes or subclasses
4	Map m:n and n-ary fact types ...