Ben böyle bir sınıf var Diyelim

class book {
    public $title;
    public $author;
    public $page_num;
        .....
        ....

 public function show_book($limit=1){
         .... 
        $result = mysql_query("SELECT title,author,page_num  FROM book limit=$limit");

         while($row = mysql_fetch_array($result))
          {
         $this->title=$row['title'];
         $this->author=$row['author'];
         $this->page_num=$row['page_num'];
          }

        }

ve sonra ben gibi kullanabilirsiniz:

 $book = new book();
 $book->show_book();
 echo $book->title." ".$book->author ...... ;

this works for one book what if i want to show 7 books ? this is not working for $book->show_book($limit=7); i can make 7 objects but i think there's a better way