Привязка 2 книг к одному автору - Prolog

Domains
    book_name,author=string
    file=f
Database
    catalog(book_name,author)
Predicates
    m(char)
    menu
    start
Clauses
 
menu:-
     clearwindow, 
     write("1 Search book name by     author;"),nl,
     write("2 Search information      about author by book    name;"),nl,
     write("3 New entry in the book   catalog;"),nl, 
     write("4 Change name of the      book;"),nl, 
     write("5 Delete record from the  book catalog;"),nl,
     write("0 Exit."),nl,
     readchar(C), m(C). 
m('1'):- 
       clearwindow, 
       write("Enter author:"), nl, 
       readln(Auth),
       catalog(Name, Auth), 
       write("Book name: "),nl,
       write(Name), 
       readchar(_), 
       menu,!.
m('1'):-write("Book with no author in the catalog!"),readchar(_),menu.
m('2'):- 
       clearwindow, 
       write("Enter name of the book:"),nl,
       readln(Name),
       catalog(Name, Auth),
       write("Author: "),nl,
       write(Auth),
       readchar(_),
       menu.
m('2'):-write("In DB is not such a book with the author!"),readchar(_),menu.
m('3'):- 
       clearwindow, 
       write("Enter name of the book:"),nl,
       readln(Name),
       write("Enter author:"),nl,
       readln(Auth),
       assert(catalog(Name,Auth)),write("Successful adding!"),readchar(_), menu,!.
m('3'):-write("Error!"),readchar(_),menu.
m('4'):- 
       clearwindow, 
       write("Enter author:"),nl,                                       
       readln(Auth),
       write("Enter new name of the   book:"),nl,
       readln(Name),
       retract(catalog(_,Auth)), 
       assert(catalog(Name,Auth)),write("Renaming was successful!"),readchar(_),menu,!.
m('4'):-write("Error!"),readchar(_),menu.
 
m('5'):- 
       clearwindow, 
       write("Enter book name,a recordof which must be removed"), nl, 
       readln(Name), 
       retract(catalog(Name,_)),write("Successful removed!"),readchar(_), 
       menu,!.
m('5'):-write("Error"),readchar(_),menu.
m('0'):- 
    save("catalog.ddb "), 
    retractall(_).
m(_):- 
       menu. 
start:-
       existfile("catalog.ddb"),!, 
       consult("catalog.ddb"),
       menu. 
start:-
       openwrite(f,"catalog.ddb"),
       closefile(f),
       menu. 
GOAL 
Start