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Querying DAOs with Set<Something>

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forgotmyusernameagain2

Post subject: Querying DAOs with Set<Something>

Posted: Sat Oct 14, 2006 8:39 am

Beginner

Joined: Sun Sep 24, 2006 11:48 am
Posts: 21

I have a class called User and with a criteria search I make some User queries....

All users from the query where unique...nobody appeared several times.

Then I added the method

public Set<Picture> getPictures();

and all the previous queries now returned some sort of joined resultset where usernames appeared several times......

So I added:

criteria.setFetchMode("pictures", FetchMode.SELECT);

to every query and it is okay again......

BUT: I think I must be using some "wrong" Annotations...or why would Hibernate join the Picture table in a way usernames appear several times?
That's my User class:

Code:

@ManyToOne
@JoinColumn(name="uid")

   public User getUser() {
      return user;
   }

        @OneToMany (fetch=FetchType.EAGER)  

// if I dont use Eager I get lazy exceptions, so I have to use it!

   @JoinColumn(name="uid")
   
   public Set<Picture> getPictures(){
      return _pictures;
   }

That's my Picture class:

Code:

public class Picture implements java.io.Serializable {

   // Fields    

   private int picid;

   private User user;

        @ManyToOne
   @JoinColumn(name="uid")

   public User getUser() {
      return user;
   }

...

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Nopalin

Post subject:

Posted: Sat Oct 14, 2006 2:55 pm

Newbie

Joined: Sat Oct 07, 2006 2:48 pm
Posts: 17

if you has one-to-many relationship, you should to do something like this:

Code:

@Entity
public class User implements java.io.Serializable
{
    int id;
    Set<Picture> pictures;

    @OneToMany(mappedBy="user") //the name od the property
    public Set<Picture> getPictures()
    {
        return pictures;
    }
}


@Entity
public class Picture implements java.io.Serializable
{
    int id;
    User user;

    @ManyToOne(fetch=FetchType.LAZY)
    public User getUser()
    {
         return user;
    }
}

What is the criteria you used?

Whit this example, when you get a persisted User, you can do getPictures, and hibernate will find all pictures where property user equals to the entity are using.

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