Read carefully and draw Entities .

A publishing company produces scientific books on various subjects. The books are written by authors who specialize in one particular subject. The company employs editors who, not necessarily being specialists in a particular area, each take sole responsibility for editing one or more publications. A publication covers essentially one of the specialist subjects and is normally written by a single author.

When writing a particular book, each author works with one editor, but may submit another work for publication to be supervised by other editors. To improve their competitiveness, the company tries to employ a variety of authors, more than one author being a specialist in a particular subject.

2. Read again and draw relationships.

3. Check Check Your ER dragram  with following data sets

1. Two Books on ICT A/L and Math A/L Authored by Mr. Perera Edited by Mrs. Perera and Ms. Perera Respectively. Dr. Perera  only Edit Electronic books. Professor Perera edit all books.

How will you store that data as records in a DBMS?
What keys would you used to obtain following results?

1. Books Edited by Ms. Perera
2. Editors of ICT A/L Book
3. Books NOT edited by Dr. Perera

4. What if Professor Perera want to Write a Physics A/L Book?
What modification would you suggest ?