Case Scenario: a private book collector is designing a database to keep track of her purchases and book holdings. Consider the entity set Book with attributes title, author, publisher, pubDate, numberPages, condition, cost, and datePurchased. There is an entity set called Purchase with attributes purchaseDate, totalAmount, and any others you wish to add to describe book purchases. A purchase may include several books.
Requirement:
1. Make an E-R diagram to show how this entity set (Purchase) and its relationship to Book would be represented. Indicate primary keys. Stating any necessary assumptions, make a decision about the cardinality and participation constraints of the relationship, and add appropriate symbols to the E-R diagram.
2. 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. Making up attributes as needed, add this entity and appropriate relationship(s) to the diagram.