Every table in
a table hierarchy must be assigned to a named row type in a corresponding
type hierarchy. The following figure shows an example of the relationships
that can exist between a type hierarchy and table hierarchy. Figure 1: Example of the relationship
between type hierarchy and table hierarchy
However, you
can also define a type hierarchy in which the named row types do not
necessarily have a one-to-one correspondence with the tables in a
table hierarchy. The following figure shows how you might create a
type hierarchy for which only some of the named row types have been
assigned to tables. Figure 2: Example
of an inheritance hierarchy in which only some types have been assigned
to tables
