When the database techniques are combined with object oriented concepts, the result is an object oriented management system (ODBMS). Today’s trend in programming languages is to utilize objects, thereby making OODBMS is ideal for Object Oriented programmers because they can develop the product, store them as objects, and can replicate or modify existing objects to make new objects within the OODBMS. Object databases based on persistent programming acquired a niche in application areas such as engineering and spatial databases, telecommunications, and scientific areas such as high energy physics and molecular biology.
List of Object Oriented Database Standards
Some of the Object oriented DBMS standards are
- Object data management group
- Object database standard ODM 6.2.0
- Object query language
- Object query language support of SQL 92
Object Oriented Data Model(OODM)
Object oriented data models are a logical data models that capture the semantics of objects supported on object oriented programming. OODMs implement conceptual models directly and can represent complexities that are beyond the capabilities of relational systems. OODBs have adopted many of the concepts that were developed originally for object oriented programming language. An object oriented database is a collection of objects defined by an object oriented data model. An object oriented database can extend the existence of objects so that they are stored permanently. Therefore, the objects persist beyond program termination and can be retrieved later and shared by other programs.
Characteristics of Object oriented database
The characteristics of object oriented database are listed below.
- It keeps up a direct relation between real world and database objects as if objects do not loose their integrity and identity.
- OODBs provide system generated object identifier for each object so that an object can easily be identified and operated upon.
- OODBs are extensible, which identifies new data types and the operations to be performed on them.
- Provides encapsulation, feature which, the data representation and the methods implementation are hidden from external entities.
- Also provides inheritance properties in which an object inherits the properties of other objects.
Object, Attributes and Identity
- Attributes : The attributes are the characteristics used to describe objects. Attributes are also known as instance variables. When attributes are assigned values at a given time, it is assumed that the object is in a given state at that time.
- Object : An object is an abstract representation of the real world entity which has a unique identity, embedded properties, and the ability to interact with other objects and itself.
- Identity : The identity is an external identifier- the object ID- maintained for each object. The Object ID is assigned by the system when the object is created, and cannot be changed. It is unlike the relational database, for example, where a data value stored within the object is used to identify the object.
Object oriented methodologies
There are certain object oriented methodologies are use in OODB. These are:
- Class: A class is assumed as a group of objects with the same or similar attributes and behavior.
- Encapsulation: It is the property that the attributes and methods of an object are hidden from outside world. A published interface is used to access an object’s methods.
- Inheritance: It is the property which, when classes are arranged in a hierarchy, each class assumes the attributes and methods of its ancestors. For example, class students are the ancestor of undergraduate students and post graduate students.
- Polymorphism : It allows several objects to represent to the same message in different ways. In the object oriented database model, complex objects are modeled more naturally and easily.
Benefit of object orientation in programming language
The benefits of object orientation in programming language are:
- Minimizes number of lines of code
- Reduces development time
- Increases the reusability of codes
- Makes code maintenance easier
- Increased productivity of programmers
Merits of Object oriented database
OODBs provide the following merits
- OODBs allow for the storage of complex data structures that cannot be easily stored using conventional database terminology.
- OODBs support all the persistence required for object oriented applications.
- OODBs contain active object servers which support both distribution of data and distribution of work.
Advantages of Object oriented data model over Relational model
When compared with the relational model, the object oriented data model has the following advantages.
- Reusability: generic objects can be defined and then reused in numerous application.
- Complex data types: Can manage complex data such as document, graphics, images, voice messages, etc.
- Distributed databases: Due to mode of communication between objects, OODBMS can support distribution of data across networks more easily.
Object oriented model vs Entity Relationship model
An entity is simply a collection of variables or data items.
When an application is running, the ER Model will tells how the application’s data will be persisted but the Object Oriented Model will decide that how that data will be stored in the memory.
Advantages of OODB over RDBMS
Object oriented database advantages over RDBMS:
- Objects do not require assembly and dis-assembly saving coding time and execution time to assemble or disassemble objects.
- Reduced paging
- Easier navigation
- Better concurrency control
- Data model is based on the real world
- Works well for distributed architectures
- Less code required when applications are object oriented.
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