Re: oracle DB design question

 The fact that a reader likes to read books  of certain authors is independent of
 what the book is (hope understood this correctly ?).

 If defnied at a higher E_R level  

 Book << ---> author ( book has one author)

 Reader <<---- >> author (readers reads many books and a given book is read by many readers)

 The first relation builds for books table  Book_id (PK ) and author_id (FK)
 and
 for author table
 author_id(PK)

The second relation builds
an associative relation(table)
reader_author with
reader_id + author_id (concatenated PK) and
reader table
reader_id (PK)

HIH   Sarah T.   Received on Sun Aug 16 1998 - 11:11:44 CDT