Enum / Struct in a Union

You can use an enum or a struct in a union using a composition association. The composition allows you to define the struct as a case in the union.

union Customer switch(short) {
 case XYZ:
  char Last_Name;
 case ZYX:
  char Name;
 default:
  Identification uses;
};

The name of the attribute is on the association role and the case is on the association.