Enter data from keyboard for the following fields of several book records for a library of books:
� Book accession number
� Subject code
� Book_id
� Author
� Year of Publication
� Title of the book
� Publisher's name
� Price
� Validations to be made:
� Year of publication must be before 1996
� Book_id must be unique.
� Publisher, Author and the title of the Book cannot be entered blank.
� Subject code can only be either UNIX or C.
� The Book accession numbers must be in ascending order.