(a) Design an ER diagram for a library management system where: (i) A library has multiple books. (ii) Each book can have multiple copies. (b)…

(a) Design an ER diagram for a library management system where:

(i) A library has multiple books.

(ii) Each book can have multiple copies.

(b) Consider the following database schema:

employee (employee_name, street, city)
works (employee_name, company_name, salary)
company (company_name, city)

Write the SQL commands to perform the following operations:

(i) Find the names of all employees who live in the city 'Dhaka'.

(ii) Find the names of all employees whose salary is greater than BDT 1,00,000.

(c) Why is normalization required in a database? Write shortly about 3NF.