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1.4 Role Tool

See also the Menu Reference, Section 3.1.

The Role Tool is used to specify the components that lie at the end of a relationship connected to an object. For example, in Data Flow Diagrams we can identify two role types: From and To, or for an Inheritance relationship type in an object-oriented method there could be Superclass and Subclass role types.

Roles can have properties of their own, and also symbols. For example, in an Entity-Relationship-Attribute Diagram the roles associated with a relationship between two or more entities have a property called Cardinality. In a Data Flow Diagram, the role To has a symbol as well: the solid line with an arrow head — note that Role symbols also specify the width and colour of the line from the object to the relationship. If no symbol is defined, a simple 1-pixel black line is used.

Figure 1-7. Role Tool.


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