Question 6841 – UGC NET CS 2016 Aug- paper-3

Specialization: Specialization is a top-down approach, means higher to lower. Result of taking a subset of a higher level entity set to from a lower level entity set.
Generalization: Generalization is a bottom-up approach, means lower to higher. Result of taking the union of two or more disjoint(lower-level) entity sets to produce higher-level entity set.
Aggregation: It is treated as higher level entity sets and can participate in relationships.
Mapping cardinalities: Number of entities to which another entity can be associated via a relationship set. An abstraction in which relationship sets(along with their associated entity sets) are treated as higher level entity sets, and can participate in relationships.
Mapping cardinalities: Express the number of entities to which another entity can be associated via a relationship set.