linking to multiple subtype records
To clearly describe my problem, I'll use a library analogy:
As we all know a library has many shelfs.
Suppose one shelf always contains 1 comic book, 1 novel an 1 dictionary.
All three of these books have the same properties so they can be represented by 1 type: Book.
My database at the moment has the following tables:
BookType ( k_booktype_id, type_name ),
Shelf ( k_shelf_id ),
Book ( k_book_id, book_title ),
Shelf_Books ( fk_shelf_id, fk_book_id, fk_booktype_id ).
How can I enforce that when I create a new Shelf, automatically all Shelf_Books records for every BookType are created ?
Thanks in advance,