Generalization Specialization Ashima Wadhwa Specialization and generalization are

Generalization & Specialization Ashima Wadhwa

Specialization and generalization are main principles of database modeling. Specialization is based on a refinement of types or classes to more specific ones. Generalization maps or groups types or classes to more abstract or combined ones. Typically, generalizations and specializations form a hierarchy of types and classes.

IS A • The "IS A"-relationship and the mechanism of inheritance are powerful concepts that help to reduce the complexity of models and the redundancy in specifications. Moreover they allow for increased reuse of specifications and code.

Generalization/specialization • Generalization/specialization is an abstraction principle that allows to define classes as a refinement of other classes. The more general class is also called super type or parent class and the refined class is then called a subtype or child class.

Generalization • Generalization is a bottom-up approach in which two lower level entities combine to form a higher level entity. In generalization, the higher level entity can also combine with other lower level entity to make further higher level entity.

Generalization

Specialization • Specialization is opposite to Generalization. It is a top-down approach in which one higher level entity can be broken down into two lower level entity. In specialization, some higher level entities may not have lower-level entity sets at all.

Specialization