I have this problem:
Library has books, VDOs, CDs Journals. It gives loan to users. Books and Journals can be referential which cannot be loaned out more than 2hrs and non-referential which can be loaned out for 2 weeks. user have ID and name and address. Users can be staff and student. Staff can be FT or PT. Student can be FT and PT and Undergrad or Postgrad. Library has copies of every items. Books and Journals have one or more authors..Design a conceptual schema.
Main classes: Libraryitems, copy, loan, user, author, period-for loan time.
Generalisations: Libraryitem, user.
Specific classes: FullTime/Parttime, UG, PG for students and FT/PT for employee
Upto now am I correct in identifying the classes?