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I. Introduction istory of data processing goes through many different changes with different technologies along with the time. In decade there is huge increase in the volume of data that need to be processed due to which sometimes old technology do not work and need to come with new technology to process the data. History of database technology has used Unit Records & Punch Card, Punch Card Proliferation, Paper Data Reels, & Data Drums, File Systems, Database Systems, NoSQL and NewSQL databases. From last five decades, the mostly used technology is database management systems.

After some limitations of file systems, researchers come up with new technology known as Database Management Systems which is the collection of software or programs to maintain the data records. Initially, two models are proposed are hierarchical and network models, but these models don't get much popularity due to their complex nature. Then a researcher E.F. Codd comes up with a new data model known as relational model in which data items are stored in a table. Many DBMS's are developed on the basis of this model. This is the most popular model till now because it has conceptually foundation from relational mathematics.

In mid-1980's ,no doubt RDBMS are very much popular but due to some limitation of relation model and RDBMS do not support for some advanced applications [1] OODB comes in the picture. At that time Object Oriented Programming paradigm is very much popular. Due to this researcher think to combine the capabilities of database and object based paradigm for programming. In Object databases data is stored in the forms of objects. These database management systems are not very much popular because due to the lack of standards.

Research is going on the database technology from 1960's up to this day. Many improvements are done in database technology by researcher in last decade and more technologies are coming to improve the database technology. The new database technologies include new transaction management and concurrency control methods and Redundant Array of Independent Disks (RAID) for efficient storage and Big Data and Cloud Computing.

There are three reasons for need of OODBMS: For this you must know:

? Depth of recursive query must be known.

? You can use the transitive closure operations to handle recursive queries in RDBMS. 9. Impedance mismatch: SQL Data Manipulation Language (DML) is lack computational completeness [10]. To overcome this situation, you must embed the SQL with any high programming language like C++, Java, and C #. Due to there will be impedance mismatch between two language SQL and higher programming language. 10. Poor support for long duration transactions: In RDBMS, generally transactions are short lived and concurrency control techniques or mechanisms are not good for .long duration transactions. 11. Poor Schema Evolution support: Schema Evolution means making changes to schema of database at runtime without interrupt the execution of the application. 12. Poor Navigational Access: There is very poor support for the navigational access in RDBMS.

There are some advanced applications need the database with deeper structural and functional foundation of capabilities that are not provided by conventional database [1]. These applications are:

? In these types of applications, relevant data about buildings, airplanes and integrated circuit chips is stored and managed. In this type of applications, database design may be very large.

? Design in these types of applications is not static. This design is evolves through the times. Updates need to be propagated.

Another domain that enforces the development of OODBMS is popularity of object oriented programming paradigm [4], [5], [6], [7], [8]

The OODBMS paradigm manifesto set the minimum fundamental directional basis for an OODBMS model [3], [4], [5, [8].These characteristics can be classified as mandatory and optional features:

1. Support for complex objects: A OODBMS must support for complex objects. Complex objects can be obtained by applying constructor on basic objects. 2. Object Identity: It is the unique identifier associated with every object in the system. It has following characteristics:

? It is generated by system.

? It is unique to that object in the entire system.

? It is used only by the system, not by the user.

? It is independent the state of the object. 3. Encapsulation: An OODBMS should enforce encapsulation through access objects only.

A OODBMS must support for one of them types or classes. 5. Inheritance and Hierarchies: A OODBMS must support for concept of super classes and subclasses. The types of heritance can be:

The basic theme of OODBMS is to add persistence to OOPL as they provide object orientation. The major difference is that here database needs to store data as well as methods [1]. c) Database Server: In this approach, Client simply passes the request to the server, receives results and passes them to application. Most of database processing done at server .This approach is used mainly by RDBMS's.

VII. Achievements and Weaknesses of OODBMS a) Achievements 1. Support for User Defined data types: OODBs provides the facilities of defining new user defined data types and to maintain them [9].

OODBs allow creating a new type of relationship between objects is called inverse relationship (a binary relationship) [11]. [11]. 9. No full-fledged facilities to implement complex objects: No doubt, object oriented databases provide some facilities to implement the concept of complex objects. But there is no full -fledged implementation of complex objects [11]. 10. Interoperability between OODB and Object Oriented Systems: In Object Oriented Programming objects are transient in nature. To provide persistent to data, OODB and OO systems need to be interoperable. Many problems may arise during interoperable between OODB and OO systems [11]. 11. Limited performance gains over RDBs Decrease in performance: Performance gains changes application to application. Applications that make the use of object identity concept having performance gains over RDBMS's. But application that requires bulk database loading and does not make use of OID then performance of OODBMS's is not good [9]. 12. Some basic features are not present: Some basic features like triggers, meta data management [11] and constraints such as UNIQUE and NULL [9] not present in object databases.

VIII. Comparison of OODBMS and RDBMS

No doubt, relational databases are very popular and there are found everywhere. The object oriented database comes into action in mid-1985's to remove the limitations and to support some advanced database applications like CAD, CASE etc. Another point that provides the momentum to develop object based database is popularity of object based programming. So; researchers in the field of database think to combine the object oriented programming concepts with database to make powerful database management systems. Different approaches are adopted by industry to make the database with object oriented features. These approaches include relational extensions and pure object oriented are most popular to develop object oriented database systems. OODBMS's are made by many vendors by using different approaches. OODBMS's removes the limitations of RDBMS's, also provide support for advanced database application with some additional features. But due to the lack of standards, they do not get much popularity in the industry. Then after some time, some limitations are found in object oriented database management systems.