Add a discriminator label to a generalization
In a static structure diagram, double-click the Generalization shape you want to add a discriminator to.
In the UML Generalization Properties dialog box, for Discriminator, type the name of the discriminator you want, and then click OK.
Indicate a generalization relationship between UML elements
Drag a Generalization shape from the UML Static Structure stencil onto the drawing page near the classes or packages you want to relate.
Glue the endpoint near the arrowhead to a connection point on the more general element. Glue the endpoint without the arrowhead to a connection point on the more specific element.
Double-click the Generalization shape. In the UML Generalization Properties dialog box, add a name, stereotype, discriminator, and other property values, and then click OK.
To indicate a generalization for an association, use the Association Class shape rather than the Binary Association shape.