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Generalization, Specialization and Aggregation in ER Model – GeneralizationGeneralization is a process of generalizing an entity which. Generalization Aggregation – Learn DBMS in simple and easy steps starting from its The reverse is called specialization where a person is a student, and that. Generalization Aggregation – The concept of generalization (specialization) is associated with special types of entities known as superclasses and subclasses, .

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Notation of Generalization Generalization is represented by a triangle with a line.

In generalization, a number of entities are brought together into one generalized entity based on their similar characteristics. The concept of generalization specialization is gagregation with special types of entities known as superclasses and subclasses, and the process of attribute inheritance.

Similarly, in a school database, persons can be specialized as teacher, student, or a staff, based on what role they play in school as entities.

In basic terms, a gathering of substances in specialization can be classified into sub-bunches in view of their attributes. Specialization is opposite to Generalization. The relationship between a superclass and a subclass is one-to-one 1: Comments Edit Question Edit Categories. So rbms is a top-down methodology in which one larger amount substance can be separated into two lower level element.

Generalization Aggregation

Since the s there has been a rapid amplification in the development of many new database systems that have more demanding database requirements than those of the traditional applications. The ER Model has the power of expressing database entities in a conceptual hierarchical manner.

An example of aggregation is the ‘Teacher’ entity following the ‘syllabus’ entity act as a single entity in the relationship.


It allows generalizatino entities to inherit the attributes of higher-level entities. An entity type that includes one or more dissimilar sub-groupings of its occurrences that is required to be represented in a data model. Generalization Specialization Aggregration Let’s understand what they are, and why were they added to the existing ER Generqlization.

C Tutorials C Programs. In basic terms, Generalization is a procedure of removing normal attributes from two or more classes and joining them into a summed up superclass.

Generalization, Specialization and Aggregation in ER Model

Aggregation represents relationship between a whole object and its component. Hence, as part of the Enhanced ER Modelalong with other improvements, three new concepts were added to the existing ER Model, they were: As the basic concepts of ER modeling are often not enough to represent the requirements of the newer complex applications which therefore stimulated the need to develop additional ‘semantic’ modeling concepts.

Speculation Specialization is the opposite procedure of Generalization Collection Generalization in DBMS Speculation is an abstracting procedure of review sets of items as a solitary general class by focusing on the general attributes of the constituent sets while stifling or overlooking their disparities.

A person has name, date of birth, gender, etc.

As the complexity of data increased aggregztion the late s, it became more and more difficult to use the traditional ER Model for database modelling.

It is a top-down approach in which one higher level entity can be broken down into two lower level entity. Another type of total says that it is abstracting a relationship in the middle of articles and survey the relationship as an item.

A relationship represents a connection between two entity types that are conceptually at the specalization level. Various semantic data models have been proposed, and some of the most important semantic concepts have been successfully incorporated into the original ER model. But in a company, persons can be identified as employee, employer, customer, or vendor, based on what role they play in the company.


Generalization, Specialization and Aggregation in ER Model

A generalization is a bottom-up approach. The reflection is the instrument used to shroud the unnecessary points of interest of an arrangement of articles. For example, the attributes of a Person class such as name, age, and gender can be inherited by lower-level entities such as Student or Teacher. In generalization, the higher level entity can also combine with other lower level entities to make further higher level entity. It breaks an entity into multiple entities from higher level super class to lower level sub class.

In simple terms, Aggregation is a process when relation between two entities is treated as a single entity. In simple words, aggregation is a process where the relation between two entities is treated as a single entity. We use all the above features of ER-Model in order to create classes of objects in object-oriented programming.

Going up in this structure is called generalizationwhere entities are clubbed together to represent a more generalized view. Aggregration is a process when relation between two entities is treated as a single entity. The entity shall be a student, and further, the student is a person. Specialization is a process of identifying subsets of an entity that shares different characteristics. The normal qualities implies here properties or techniques.