table inheritance and polymorphic functions

Hello,

Is there any way to set up overloaded functions whose parameters are
composite types (i.e., row types) within a table inheritance hierarchy, so
that postgresql dispatches to the correct function depending on the actual
type of its argument, in an "object-oriented" fashion? What I mean is this.
Suppose I create a table for CITIES and another table for CAPITALS which
inherits from CITIES. Can I create same-named overloaded functions on
CITIES and CAPITALS in such a way that the "correct" function is called
depending on the actual type of the row?

Cheers,
David A. Ventimiglia
DSSG
Wells Fargo Bank

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