For each of the descriptions below perform the following tasks:
(1) identify the degree and cardinalities of the relationship (2) express the realtionships in each description graphically with an e-r diagram
(a) a book is identified by its isbn number and it has a title, a price, and a date of publication. it is published by a publisher which has its own id number and a name. each book has exactly one publisher but one publisher typically publishes multiple books over time.
(b) a book (see 2a) is written by one or multiple authors. each author is identified by an author number and has a name and date of birth. each author has either one or multiple books; in addition, occasionally data are needed regarding prospective authors who have not yet published any books.