CODEWITHSUNDEEP
javajpaplayframeworkplayframework-1.x
Fabien Henon
Fabien Henon

Reputation: 823

ew@OneToOne relationship with play framework that does not use JOIN

I have 2 models with a @OneToOne relationship. Let's say a model User and a model Player. Each user is a player and each playeris a user.

Here is the code of these 2 models :

@Entity
public class User extends Model {

    @Required
    public String name;

    @OneToOne(fetch = FetchType.EAGER)
    public Player player;
}

@Entity
public class Player extends Model {

    @Required
    public String nickname;

    @Required
    public Gender gender;
}

I will always access a Player from a User and I want that when I load a User, his Player is also loaded (that's why I used fetch = FetchType.EAGER).

So I expect (for optimization purposes) that when I load a User, the query is a JOIN query that also loads the Player. Something like :

select u, p from User u join u.player p where u.player_id = p.id

But when I look at the queries count and the queries debug output I can see that 2 queries are performed. Something like:

select u from User u
select p from Player p where p.id = ?

But this is not optimized, how can I make JPA perform a join request to get my User and its Player ?

Tank you for your help!

EDIT : I'm using Play framework 1.2.5

Upvotes: 0

Views: 823

Answers (2)

Seb Cesbron
Seb Cesbron

Reputation: 3833

In the User class, as you noticed in your comment that the player can be null

public static void findByIdWithPlayer(Long id) {
    find("select distinct user from User user left join fetch user.player where user.id=?", id).first();
}

Upvotes: 2

ndeverge
ndeverge

Reputation: 21564

EDIT: this answer applies only for Play 2.0 with Ebean.

It is not clear if you're using Ebean or plain JPA.

If it is Ebean, as explained in the doc, you have to fetch the linked entity:

List<User> orders =   
    Ebean.find(User.class)  
        .fetch("player")  
        .findList();

Upvotes: 2

Related Questions