
The Subtype properties pane includes a list box for the primary supertype (see
Figure 5–20). The primary supertype provides the default reference scheme for the sub-
type. If a subtype has only one supertype, this is its primary supertype. If a subtype has
more than one supertype, one of these must be chosen as its primary supertype. For
example, the ORM schema in Figure 5–21 exhibits multiple inheritance, because
FemaleInPatient has two supertypes. To choose the primary supertype, first select the
subtype, then choose the relevant option from the Primary supertype drop-down list box.
The tool displays the primary supertype connection as a solid arrow ...