In the context menu of a selected class you will find the function "Create Property" as well as the functions "Inheritance Connection", "Composite Connection" and "Association Connection" for creating different association types.

Creating a model reference

To create a reference, the reference type is selected and dragged directly onto the target model element.

Then a dialog opens for specifying a technical ID and other properties (e.g. cardinality) for the new reference:

Inheritance Connection

This association is used to establish an inheritance relationship:

The class "Ticket" inherits from "Subject Object

Association Connection - Reference

This association is used to create a reference. A reference is a single- or multi-valued relationship to another model element (a class or enumeration).

References differ from simple properties in that their type is not primitive (string, integer, date...), but is defined by another class.

In the example, the "Ticket" class has a 1-valued reference to the "Status" enumeration:

Composition Connection - Composition.

This association is also a reference that does not express a simple reference to a target object, but defines the target object as a component of the source object. I.e. the life cycles of these objects are linked to it. In the example a product consists of product versions:

I.e. a product version lives in the context of its product. If the product is deleted, all associated product versions also disappear.