What is generalization and specialization in database?

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.

What are the four types of specialization generalization?

Hence, we have four types of specialization/generalization:

Disjoint, total.
Disjoint, partial.
Overlapping, total.
Overlapping, partial.

What is the difference between specialization and generalization with respect to database?

Specialization is a designing procedure that proceeds in a top-down manner. Specialization is just opposite to Generalization. In specialization, we split an entity to form multiple lower level entities. These newly formed lower level entities inherit some features of the higher level entities.

What is Generalisation in DBMS?

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.

What is Generalization specialization?

Generalization is the process of extracting shared characteristics from two or more classes, and combining them into a generalized superclass. In contrast to generalization, specialization means creating new subclasses from an existing class.

What is an example of a specialization?

Economies that realize specialization have a comparative advantage in the production of a good or service. If, for example, a country can produce bananas at a lower cost than oranges, it can choose to specialize and dedicate all its resources to the production of bananas, using some of them to trade for oranges.

What is a generalization Specialization hierarchy?

A generalization hierarchy (also called is-a hierarchy) connects a superclass and one or more subclasses, representing a specialization of the superclass. Each class is defined as the specialization of at most one superclass. In technical terms, “multiple inheritance” is avoided.

What are the two constraints on Specialization generalization?

Constraints on specialization/generalization There are three constraints that may apply to a specialization/generalization: membership constraints, disjoint constraints and completeness constraints. User defined: Sometimes the designer can define the superclass-subclass relationship.

Is it better to specialize or generalize?

Choose a specialty that has a broad market. If your specialty is too narrow, you might find it somewhat limiting. Don’t choose something that will put you in less demand. In summary Generalization offers better job security than specialization does.

What is a generalization specialization hierarchy?

What is specialization in DBMS Mcq?

Explanation: The process of designating sub-groupings within the entity set is called as specialization. Specialization allows us to distinguish among entities. Explanation: We can apply specialization multiple times to refine a design.

What is specialization in DBMS explain with example?

Specialization is a process in which an entity is divided into sub-entities. For example – Consider an entity employee which can be further classified as sub-entities Technician, Engineer & Accountant because these sub entities have some distinguish attributes.