A. Assume that in the same scenario as in Exxercise 3.2, there is an entity set called Purchase with attributes purchaseDate, total amount, and any others tou wish to add to describe book purchases. A purchase may include several books. Show how this entity set and its relationship to book would be represented on the E-R diagram. b. Stating any necessary assumptions, make a decision about the cardinallity and participation constraints of the relationship, and add appropriate symbols to the E-R diagram.
c. Assume there is another entity called Seller to be added to the diagram. The book collector makes purchases from many sellers, but each purchase is made from one seller. amaking up attributes as needed, add this entity and appropriate relationship(s) to the diagram.