In addition, object-oriented purists are not attracted by these extensions either. They
argue that the terminology of object-relational systems is revealing. Instead of discussing
object models, terms like ‘user-defined data types’ are used. The terminology of objectorientation
abounds with terms like ‘abstract types’, ‘class hierarchies’, and ‘object models’.
However, ORDBMS vendors are attempting to portray object models as extensions to the
relational model with some additional complexities. This potentially misses the point of
object-orientation, highlighting the large semantic gap between these two technologies.
Object applications are simply not as data-centric as relational-based ones. Object-oriented
models and programs deeply combine relationships and encapsulated objects to more
closely mirror the ‘real world’. This defines broader sets of relationships than those
expressed in SQL, and involves functional programs interspersed in the object definitions.
In fact, objects are fundamentally not extensions of data, but a completely different concept
with far greater power to express ‘real-world’ relationships and behaviors.