Mapping Two One-To-One associations with the same type

plusplus · **Joined:** Fri Dec 29, 2006 12:20 pm **Posts:** 8

Hi

I have a User that has two Folders, SentFolder and SavedFolder. How can I map the associations?

Is this correct?

Code:

public class Folder {
    @OneToOne(cascade = CascadeType.MERGE)
    private User user;
}

public class User {
    @OneToOne(mappedBy = "user")
    protected Folder sentFolder;
    @OneToOne(mappedBy = "user")
    protected Folder savedFolder;
}

This approach is not correct, because both of the associations is mapped via just one foreign key.

ellen · **Joined:** Sun Sep 11, 2005 7:46 pm **Posts:** 15

How about try to make two subclasses of the Folder class, let's call them SentFolder and SavedFolder. So the cardinality between SentFolder and User is OneToOne and the cardinality between SavedFolder and User is also OneToOne. You can then add their references into the User class.

plusplus · **Joined:** Fri Dec 29, 2006 12:20 pm **Posts:** 8

I'm doing that now, but I thought this may not be a good answer. Cause I'm introducing new entities and classes into my domain just to solve my problem.

Still I'm searching for a better solution. Thanks anyway.

satsranchuser · **Posted:** Wed May 30, 2007 2:19 pm

These are value types and not entities. Entities are something that you physically map to a table.