CODEWITHSUNDEEP
hibernatejpajoin
NiMa Thr
NiMa Thr

Reputation: 978

Fetch all rows of the two joined tables at once

I'm trying to write a piece of code to fetch all of the ContactDevices with their associated Contact at once as a list (through execution of only one sql-statement).

Criteria sq = session.createCriteria(ContactDevice.class)
                .setFetchMode("contact", FetchMode.JOIN);
List<ContactDevice> contactList = (List<ContactDevice>) sq.list();

The problem is for every ContactDevice, hibernate fetches it's associated Contact through running a separate sql-statement which makes my program considerably slow, I mean hibernate runs this for each ContactDevice to get it's associated Contact :

select * from Contact contact0_ where contact0_.ContactID=?

I also tried a seemingly more manual approach but still couldn't prevent hibernate, Is there any way that I can do this by the cost of only running one sql-statement ?

@Entity
public class Contact {    
@Id
@Column(name = "ContactID")
private Integer id;    
private String firstName;
private String secondName;    
private String avatarPath;
}

@Entity
public class ContactDevice {    
@Id
@OneToOne
@JoinColumn(name = "ContactID", referencedColumnName = "ContactID")
private Contact contact;
private String phoneNumber;
private String deviceType;
}

Upvotes: 0

Views: 45

Answers (2)

NiMa Thr
NiMa Thr

Reputation: 978

Thanks guys, your hints helped me a lot. And at last I figured a way and it was to disable the proxy to get rid of this persisting laziness !

public class ContactDevice {    
    @Id
    @OneToOne
    @LazyToOne(LazyToOneOption.NO_PROXY)
    @JoinColumn
    private Contact contact;        
    .....
}

Now tuples could be retrived through both

Criteria sq = session.createCriteria(ContactDevice.class).setFetchMode("contact", FetchMode.JOIN)

or 

Query query = session.createQuery("select cd from ContactDevice cd join fetch cd.contact");

Upvotes: 1

Vlad Mihalcea
Vlad Mihalcea

Reputation: 153940

Try with a simple HQL query like this:

Query query = session.createQuery("select cd from ContactDevice cd join fetch cd.contact");
List list = query.list();

Upvotes: 0

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