Using class queries to select all rows and return an array: unexpected behaviour

We have in DB two books, first is loaned because it has the Friend ID, and the other is in the shelf.

I execute a class query to get all loaned books:

    Query BooksLoaned() As %SQLQuery
    {
        SELECT *
        FROM Library.Book
        WHERE Friend IS NOT NULL
    }
 

Which I have tested throught the portal:

My task is to retrieve all the loaned books and return them in an array. Method code:

ClassMethod GetLoanedBooks() As %ArrayOfObjects
    {
        set booksRS = ##class(%ResultSet).%New("Library.Book,BooksLoaned")
        set rsStatus = booksRS.Execute()
        set i = 1
        set ^books = ""
        if rsStatus = $$$OK {
            while booksRS.Next() {
                set book = ##class(Library.Book).%New()
                set book.Title = booksRS.Get("Title")
                set book.Author = booksRS.Get("Author")
                set book.Genre = booksRS.Get("Genre")
                set dbFriend = ##class(Library.Person).%OpenId(booksRS.Get("Friend"))
                set book.Friend = dbFriend
                set ^books(i) = book
                set i = i + 1
            }
        }else{
            w !,"Error fetching books in GetoanedBooks()"
        }
        do booksRS.Close()
        return ^books
    }
 

The question is:

Why when I execute in the terminal:

set books = ##class(Library.Book).GetLoanedBooks()
zw books

It outputs:

And when I write:

zw ^books

I know ^books is a global variable, but I do not know why if I am currently returning the books array and setting it into the terminal, it doesn't have the loaned book inside.

Thanks for your help.

Any recommended lecture is appreciated!

🤯