/    /  DBMS – Extended E-R Features Part2

Extended E-R Features


Attribute Inheritance:


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.