ER-models in DBMS


#1

When number of entities are bought together into one entity based on their similar characteristics ,what is the process called?


#2

When numbers of entities are brought together into one entity based on their similar characteristics, then the process is called Aggregation.

Consider an example:

A Researcher is working for a project may require some online tutorials. So, REQUIRE relationship is needed in between relationship WORKS_IN and the entity TUTORIAL. WORKS_IN relationship with its entities RESEARCHER and PROJECT is aggregated into single entity and relationship REQUIRE is created between aggregated entity and TUTORIAL.


#3

When number of entities are bought together into one entity based on their similar characteristics ,what is the process called Generalization