what is specialization and generalization in dbms
Generalization : It is a bottom – up approach in which multiple lower
level entities are combined to form a single higher
level entity. It is usually used to find common
attributes among entities to form a generalized entity.
Specialization : It is a top – down approach in which a higher level
entity is divided into multiple lower – level entities.
In addition to sharing the attributes of the higher
level entity, these lower – level entities have specific
attributes of their own. It is usually used to find
subsets of an entity that has a few different,
or additional attributes.
Aggregation : It is a process in which a single
entity alone is not able to make sense in a relationship.
So, a relationship of 2 entities acts as 1 entity.
It is a way of composing different abstractions together
in defining a class.