Mapping almost ok, one value dont presists.

trashhash · **Joined:** Thu Jan 11, 2007 11:27 am **Posts:** 11

I have mapped two entities with OneToMany through an HashMap. It seems to work rather good, except one thing. When Im adding a new HashMap to my Author and then try to update the values will be presisted except for the joincolumn in the booktable. Its always null. No exception is thrown.

Author

Code:

@Entity
public class Author { 
   private Long id;
   private String name;
   private Map <String, Book> bookList = new HashMap <String, Book> ();   

   [...]

   @OneToMany(mappedBy="author",targetEntity=Book.class,fetch=FetchType.EAGER,cascade=CascadeType.ALL)
   @MapKey(name="id")
   public Map<String,Book> getBookList() {
      return bookList;
   }

}

Book

Code:

public class Book { 
   
   private String id;
   private String name;
   private Long authorId;
   private author;
   
   [...]
   
   @ManyToOne(fetch = FetchType.EAGER)
   @JoinColumn(name="author_id",referencedColumnName="id")
   public Author getAuthor() {
      return author;
   }   
         

}

jsp

Code:

   [...]
   bookList.put(new Book("Foo","Bar"));
   Author author = authorService.getAuthorById(1L);
   author.setBookList(bookList);
   authorService.updateAuthor(author);

Q: Why is the author_id in book table never set.

Q: The old posts remains untouched i the table. Replacing an collection with objects should replace all post in the table(some thing like "delete from Book where author_id = ..." )

Enviroment:
Java 1.6 / 6
Mysql 5.x
jboss-4.0.5.GA

Thanks!

emmanuel · **Posted:** Fri Feb 02, 2007 11:32 am

because it's a bidirectional relationship and thus both sides have to be updated.

trashhash · **Joined:** Thu Jan 11, 2007 11:27 am **Posts:** 11

Thanks for your answer. I still dont got it to work. Even if update author and related books. Its that what you mean by both sides? If add an collection to entity I shouldnt need to set the keycolumn by my self, Hibernate will do that for me... right?

Code:

Book book = new Book("foo","bar");
book.setAuthorId(author.getId()); // this line is a waste, right? Hibernate will do it for me as soon as I add the book to the Author collection and presist?

Thanks for your time, I will be dealing out points as soon as I mange to solve this...

---- EDIT ----

Sollutions: Hopes this helps someone.

What emmanuel means is this.

Code:

Book book = new Book("Foo","Bar");
Author author = authorService.getAuthorById(1L);
book.setAuthor(author); //One side
bookList.put(new Book("Foo","Bar"));
author.setBookList(bookList); // Second side
authorService.updateAuthor(author); //Presist