Extended E-R Features
The attributes of a high-level entity get inherited by the lower-level entity sets.
For example, the entities ‘Employee’ and ‘Student’ inherit the attributes of the entity ‘Person’.
- A higher-level entity set with attributes and relationships that relate to all lower-level entity sets in it
- Lower-level entity sets with different features that relate only to a particular lower-level entity set.
Total Generalization / Specialization :
In Total Generalization/ Specialization, each high-level entity should belong to a lower-level entity set.
Partial Generalization / Specialization :
In partial generalization/ Specification, only a few higher-level entities may not belong to a lower-level entity set.
Extended E-R Features Part 2.