Transitive persistence problem using parent/child model

FranklyDing · **Joined:** Sat Oct 03, 2009 2:29 am **Posts:** 1

Hi everybody
I have problems using parent/child model. I followed Bid-Item example from the book "Java Persistence with Hibernate". Can anybody help me out?

Here is the Bid class

Code:

@Entity
public class Bid implements Serializable {

  @Id
  @GeneratedValue
  private Long bid_id;
  private String name;

  @ManyToOne ( targetEntity=Item.class, cascade = { CascadeType.ALL })
  @JoinColumn(name="itemid", nullable=false)
  private Item item;

  public Item getItem() {
    return item;
  }

  public void setItem(Item item) {
    this.item = item;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }
}

And Item class

Code:

@Entity
public class Item implements Serializable {

  @Id
  @GeneratedValue
  private Long item_id;
  private String name;

  @OneToMany(mappedBy="item", cascade={CascadeType.PERSIST, CascadeType.MERGE})
  private Set<Bid> bids = new HashSet<Bid>();

  public Set<Bid> getBids() {
    return bids;
  }

  public void setBids(Set<Bid> bids) {
    this.bids = bids;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }
}

They are copied from page 260-269.

My test program is listed below.

Code:

    SessionFactory sFactory = config.buildSessionFactory();
    Session s = sFactory.openSession();
    s.beginTransaction();

    Item item = new Item();
    item.setName("item");
    Bid bid1 = new Bid();
    bid1.setName("bid1");

// In book, the following two lines is replaced by Item.addBid()
    bid1.setItem(item);
    item.getBids().add(bid1);

    s.save(item);
    s.flush();
    s.getTransaction().commit();
    s.close();

According to the book, bid1 should also be persisted. But in fact, I have only item record but no bid in database.

What's the problem here?

Thanks.

Froestel · **Posted:** Sun Oct 04, 2009 7:44 am

Hi FranklyDing,

FranklyDing wrote:

Code:

...
  @OneToMany(mappedBy="item", cascade={CascadeType.PERSIST, CascadeType.MERGE})
  private Set<Bid> bids = new HashSet<Bid>();
...

...

Code:

...
    s.save(item);
...

You should use cascade="save-update" for the annotation of the bids if you persist your entity with Session.save() (as the book says if you read carefully).

CU
Froestel