What is Generalisation and specialization?
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 is the difference between generalization and specialization?
The key difference between Generalization and Specialization in DBMS is that a Generalization is a Bottom-up approach. while Specialization is a Top-down approach. Generalization is a bottom-up design process that combines a number of entity sets that have the same features into a higher-level entity.
What is the difference between generalization and specialization explain with example?
The fundamental difference between generalization and specialization is that Generalization is a bottom-up approach. However, specialization is a top-down approach. Generalization is always applied to the group of entities whereas, specialization is always applied on a single entity.
What is generalization explain with example?
Generalization, in psychology, the tendency to respond in the same way to different but similar stimuli. For example, a child who is scared by a man with a beard may fail to discriminate between bearded men and generalize that all men with beards are to be feared.
Which of the following is a specialization generalization constraints?
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.
What’s the difference between a specialization and a generalization?
Specialization is a process of taking a subset of a higher level entity set to form a lower-level entity set. Generalization process starts with the number of entity sets and it creates high-level entity with the help of some common features.
How is a person added to a specialization?
The key of the generalization entity (PERSON) is added into the specialization entities (ACTOR, CRICKETER, POLITICIAN). The primary key (personCode) of the generalization will be the same primary key as that of the specialization.
How are generalization and specialization used in the ER model?
The Enhanced ER Model 1 Generalization. Generalization is a bottom-up approach in which two lower level entities combine to form a higher level entity. 2 Specialization. Specialization is opposite to Generalization. 3 Aggregration. Aggregration is a process when relation between two entities is treated as a single entity.
How is specialization related to Aggregration and aggregation?
In specialization, a higher level entity may not have any lower-level entity sets, it’s possible. Aggregration is a process when relation between two entities is treated as a single entity. In the diagram above, the relationship between Center and Course together, is acting as an Entity, which is in relationship with another entity Visitor.
