ABSTRACTION: Most database systems initially concentrated on handling typical business data such as: Columns of numbers, short text, and dates. With the advent of powerful and affordable multimedia computers, people increasingly need databases to store more complex objects. Typical objects include graphics, sound, and video clips. For some applications, like geographic Information Systems(GIS) and computer-aided design (CAD), developers need the ability to define their own objects. Storing objects involves two aspects: storing data for their properties and storing and activating their methods. The first part- storing properties – is relatively easy. In relational database, the properties becomes columns. Relational databases can be adapted to handle objects. On of main components is the ability to define new data types. These data types are treated as objects, and they can inherit properties from other data types.Many commercial applications are created using OO methodologies. Given that several object-oriented applications might need to share the same data, we describe how such applications can interoperate with each other. By exposing the internal object properties and methods, the developers can use the applications to create the complex integrated business applications. The applications can use all the features of a spreadsheet, word processors, or graphics packages.This technology also provides function as well as data together so that the data can be manipulated by the given function. we show that how the data is more secure in object-oriented database than in relational database and also why do we migrate from RDBMS into OODBMS.In this paper, we describe the major characteristics and requirements of object-oriented applications and how they may affect the choice of a system and method for making objects persistent in that application.