hmm..Why is it that you dont need to create table if its already identified as an entity? My point was inverse condition ie having more than one tables to represent same entity. I cant think of a case where you wont have a table for an already identified entity
dear visakh: I meant, is it necessary to create tables for each entity in the ERD? if your answer is possitive then tell me the solution. I create ERD for a hospital and the reference relationship became the associative entity in this case I dont need to create table for reference. is it right?