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In object-oriented data models entity is represented as a class. A class within it contains data and methods. Data are attributes of object and methods are behaviour. Object-oriented supports abstract data types, i.e., one class may contain another class as its attribute.Object-oriented data model is ideal for complex data types, such as video, audio, image. Object-oriented databases support all the features of object-oriented methodology, such as message passing (methods can pass messages to other objects), class inheritance, method overriding, encapsulation, polymorphism, and operator overloading.

Following are the advantage and disadvantages of an object-oriented data model:

Advantage:

1. It is easy to handle complex data types.

Disadvantages:

1. It is difficult to understand and use compared to relational model.
2. It does not have ad hoc query capability.
3. Integrity issues are involved. On updation or deletion of parent object, child object is not updated or deleted automatically. Procedural code should be written for that.
4. Object-oriented systems are procedural, which are 3GL languages. It does not support SQL which is 4GL. Therefore, it is a step back from 4GL to 3GL.
5. Data dictionary is not managed automatically. Staff is required to do so.

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