title: When do relationships in ERD diagrams get a separate table in a RDBMS
body: <p>Title is the question.  When should a relationship in an ER diagram be given its own table in a RDBMS?  For instance, one mail courier(with attributes eid and surname) can deliver a number of packages but a package(attributes,pid, sent_By, going_to) can only have one mail courier.  Would it make sense to make a table for the relationship called delivers(with an attribute of the time that the package was delivered)? or should the eid of the mail_courier and time_delivered from the deliver relationship be added to the package entity? Also, what would be an example when you would not want to add the attributes to the package entity?</p>