In enhanced entity-relationship (EER) modeling, generalization is a ______…

Concept

In enhanced entity-relationship modeling, the direction of abstraction distinguishes generalization from specialization.

Generalization combines multiple lower-level entity types that share attributes or relationships into a higher-level supertype; specialization moves in the reverse direction, from a supertype to subtypes.

Application

The process described as generalization therefore starts with lower-level entity types, identifies their common features, and moves upward to a common supertype. Its direction is bottom-up.

Contrast

• Top-down describes specialization: a broad supertype is divided into narrower subtypes.

• Bottom-up describes generalization: related lower-level types are combined under a common supertype.

• The two directions name inverse EER operations, so they are not one bidirectional process.

• One of the listed directions does describe generalization, so excluding both directions does not fit.

Cross-check

If Student and Employee share attributes such as name and address, generalization places those common features in a higher-level Person supertype. The movement from Student and Employee upward to Person confirms the bottom-up direction.

Therefore, generalization is a bottom-up process.