In class Exercises: Exercise $2$

DRAW AN ER DIAGRAM FOR A LIBRARY DBMS ACCORDING TO THE FOLLOWING SPECIFICATION:

a$.$ The library DBMS must manage information about "Books" and "Borrowers" and

"Borrower's$-$Friend".

b$.$ Book: is the main object in the library and the DBMS must keep track of:

i$.$ the book's ISBN$($Unique number of each book$),$

ii$.$ Title,

iii. Category the book belongs to $($each book can belong to many categories, for

example. "Fundamentals of Database" book belongs to the categories: CS$,$ CIS, and

MIS$)$

iv$.$ And a book can be a new version of another book.

c$.$ Borrower: are persons who have a subscription to borrow from the library and can

borrow a maximum $5$ books at a time. The DBMS must keep track of the:

i$.$ Borrower's ID$,$

ii$.$ Name,

iii. Subscription type $($each borrower can have only one type of subscription which is

Gold, Silver or Bronze$),$

iv$.$ Number of Books borrowed,

v$.$ And the expected return date of each borrowed book.

vi$.$ Each borrower can only have one friend. All borrowers can't subscribe unless they

borrow at least one book.

d$.$ Borrower's$-$Friend: is a person who is a friend of a subscribed borrower and can borrow a

maximum of one book at a time. The friend doesn't have an ID$,$ so the DBMS must keep track

of:

i$.$ The friend's name,

ii$.$ The book he borrowed,

iii. And the date he borrowed the book.

iv$.$ Each "Borrower's$-$Friend" can be a friend of only one borrower.

So$,$ draw your ER diagram ensuring all required information is present in your

ER model and write down any assumptions you make. Identify Entities,

attributes, Relationships, and constraints.