Table 28.2 Data modeling comparison of ORDBMS and OODBMS.
Feature ORDBMS OODBMS
Object identity (OID) Supported through REF type Supported
Encapsulation Supported through UDTs Supported but broken for queries
Inheritance Supported (separate hierarchies Supported
for UDTs and tables)
Polymorphism Supported (UDF invocation Supported as in an objectbased
on the generic function) oriented programming model language
Complex objects Supported through UDTs Supported
Relationships Strong support with user-defined Supported (for example, using
referential integrity constraints class libraries)