Object orientation in relational databases

There is, as yet, no single formal definition for the object-oriented approach. The object-oriented paradigm is described in terms of the concepts accentuated by the approach, namely classes, objects, methods, messages and class hierarchies. In view of these concepts, the object-oriented approach supports the properties of encapsulation, inheritance and polymorphism. The object-oriented approach stands in contrast to many aspects of the relational data model traditionally used in databases. The data in a relational database is viewed as a semi-passive component, while the objects in the object­-oriented approach are viewed as active components. The relational data model and the object-oriented approach also differ in many other respects. Second generation relational database management systems do provide features which make them more object­ oriented than their traditional first generation counterparts. In order to develop applications utilizing these systems, it may be necessary to consider object-oriented approaches. Ingres, as an example of a second generation relational database management system, provides some of the concepts of the object-oriented paradigm and it supports some of the properties of the object-oriented approach