ORDBS provide a migration path for users of relational data model who wish to use OO features.
Back in the Oracle 7 days (maybe even earlier), Object-Oriented Programming (OOP) was becoming all the rage with development platforms like C++ and Java. Oracle and other database vendors added object-oriented functionality natively in the database. The hope was that OOP development platforms would be able to talk to the database better if they were speaking the same language. Pushing object-oriented functionality into the database resulted in the term Object-Relational Database Management System (ORDBMS). This is still a relational database, but it also supports object.
