EDGY defines three types of relationships each of which can connect two elements to express their interplay. This limited number reflects a deliberately simplified model compared to other visual languages used in engineering practice.
Using just three relationships, various enterprise elements can be collected and connected:
A link relationship describes an association between two elements.
A flow relationship describes a behaviour or dynamic sequence between two elements, and the passing of objects between them.
A tree relationship describes a containment or aggregation between a parent and a child element of the same type.
Relationships connect elements
The link relationship is an association between two elements. By default it is non-directional and unnamed and just shows that the two elements are related. Links can also be made directional by giving them a direction and a name.
The flow and tree relationships are unidirectional, describing a source and a target endpoint.
If a bi-directional connection between elements is intended, two relationships should be defined: one from element A to element B and one from B to A.
All three relationships can be displayed visually as a line or arrow, but also expressed implicitly through proximity, containment, indentation or alignment on a grid.