Answer Posted / rohit kumar singh
In many of the cases an entity type has numerous sub grouping of its entities that are meaningfull . Let understand with an example . EMPLOYEE entity type may be grouped further into ... SECRETARY , MANAGER , ENGINEERand so on .
The set of entities in each of latter grouping is a subset of the entities that belongto the EMPLOYEE entity set .
We call each of these subgrouping a subclass of the EMPLOYEE entity type , and the EMPLOYEE entity type is the superclass gor each of these subclasses.
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