The data model is a simple network, and link and intersection record types (called junction records by IDMS) may exist, as well as sets between them. An owner record type can also be a member or owner in another set. A member record type can have that role in more than one set, hence the multiparent concept is supported. A set consists of an owner record type, a set name, and a member record type. The basic data modeling construct in the network model is the set construct. In 1971, the Conference on Data Systems Languages (CODASYL) formally defined the network model. So, the network model permitted the modeling of many-to-many relationships in data. Some data were more naturally modeled with more than one parent per child. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, is not restricted to being a hierarchy or lattice.The popularity of the network data model coincided with the popularity of the hierarchical data model. The Network Database Model is a database model conceived as a flexible way of representing objects and their relationships. At the same time, they must adhere to numerical constraints that are normally not found in traditional databases. MMDBs are required to provide unified frameworks for storing, processing, retrieving, transmitting and presenting a variety of media data types in a wide variety of formats. Apart from those, a MMDB has to provide some new and enhanced functionalities and features. MMDBs are supposed to provide almost all the functionalities, a traditional database provides. Some inherent qualities of multimedia data have both direct and indirect influence on the design and development of a multimedia database. The applications include digital libraries, manufacturing and retailing, art and entertainment, journalism and so on. MultiMedia Databases (MMDBs) have to cope up with the increased usage of a large volume of multimedia data being used in various software applications. From an user perspective, databases provide functionalities for the easy manipulation, query and retrieval of highly relevant information from huge collections of stored data. The huge amount of data in different multimedia-related applications warranted to have databases as databases provide consistency, concurrency, integrity, security and availability of data. This makes object DBMSs better suited to support applications such as financial portfolio risk analysis systems, telecommunications service applications, world wide web document structures, design and manufacturing systems, and hospital patient record systems, which have complex relationships between data. This one-to-one mapping of object programming language objects to database objects has two benefits over other storage approaches: it provides higher performance management of objects, and it enables better management of the complex interrelationships between objects. In contrast to a relational DBMS where a complex data structure must be flattened out to fit into tables or joined together from those tables to form the in-memory structure, object DBMSs have no performance overhead to store or retrieve a web or hierarchy of interrelated objects. The power of the OODB comes from the seamless treatment of both persistent data, as found in databases, and transient data, as found in executing programs." Object developers can write complete database applications with a modest amount of additional effort.Īccording to Rao (1994), "The object-oriented database (OODB) paradigm is the combination of object-oriented programming language (OOPL) systems and persistent systems. As a result, applications require less code, use more natural data modeling, and code bases are easier to maintain. A major benefit of this approach is the unification of the application and database development into a seamless data model and language environment. Object DBMSs extend the semantics of the C++, Smalltalk and Java object programming languages to provide full-featured database programming capability, while retaining native language compatibility. They bring much more than persistent storage of programming language objects. Object-Oriented Database Model add database functionality to object programming languages.
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