Generalization in dbms
In a database management system (DBMS), generalization is the process of organizing data into more general and abstract categories. This is typically done to reduce redundancy and improve the efficiency and effectiveness of the database.
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| DBMS generalization | SKILLS ARENA |
Generalization is a bottom-up approach in which multiple lower-level entities are combined to form a single higher-level entity. Generalization is usually used to find common attributes among entities to form a generalized entity. It can also be thought of as the opposite of specialization.
The following enhanced entity relationship diagram expresses entities in a hierarchical database to demonstrate generalization:
Difference between generalization and specialization in dbms
Purpose: Generalization is the process of creating a more general concept or class by merging similar specific concepts or classes, while specialization is the process of creating a more specific concept or class by breaking down a more general concept or class.
Direction: Generalization is a top-down process, while specialization is a bottom-up process.
Output: Generalization produces a broader, more abstract concept or class, while specialization produces a narrower, more concrete concept or class.
Number of concepts or classes: Generalization results in fewer concepts or classes, while specialization results in more concepts or classes.
Inclusion of attributes: Generalization includes fewer attributes, while specialization includes more attributes.
Granularity: Generalization is a more coarse-grained process, while specialization is a more fine-grained process.
Relationship between concepts or classes: In generalization, the resulting concept or class is a superclass of the original concepts or classes, while in specialization, the resulting concepts or classes are subclasses of the original concept or class.
Inheritance: Generalization involves the creation of an inheritance relationship between concepts or classes, while specialization involves the refinement of an inheritance relationship.
Abstraction level: Generalization involves a higher level of abstraction, while specialization involves a lower level of abstraction.
Use: Generalization is used to identify commonalities between concepts or classes, while specialization is used to identify differences between concepts or classes.
For example, let's say a database contains information about various employees in a company. Each employee has a unique identifier, name, position, salary, and address. If the database contains information about multiple employees who have the same position, such as "Manager", it would be inefficient to store the position for each individual employee. Instead, we can use generalization to create a separate "Position" table that stores the position name and a unique identifier for each position. We can then use this identifier to reference the position for each employee in the "Employees" table. This reduces the amount of data that needs to be stored, and makes it easier to update and maintain the database.
Generalization can also be used to create a hierarchy of categories. For example, we can create a "Department" table that stores the name and unique identifier for each department in the company. We can then use this identifier to link each employee to the department they work in. This allows us to easily organize and retrieve information about employees by department.
Overall, DBMS generalization is an important concept in database design, as it helps to reduce redundancy and improve the efficiency and effectiveness of the database.
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Created by-- HARSH CHAUHAN
