map a bidirect many-to-one association with a joinTable ?

tiggy · **Joined:** Fri Oct 06, 2006 2:49 am **Posts:** 25

Hi all,

I am having troubles to map a bidirectional many-to-one association with a Join table?

Code:

public class A {
....
@ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE }, fetch=FetchType.LAZY, targetEntity=B.class)
    @JoinTable(
        name="A_B",
        joinColumns=@JoinColumn(name="A_ID"),
        inverseJoinColumns=@JoinColumn(name="B_ID")
    )
    @IndexColumn(name = "position", base=0)
    private B b;
...
}

public class B {
...
@OneToMany(mappedBy="b", fetch = FetchType.LAZY, targetEntity=A.class)

    private List<A> myList = new ArrayList<A>();
...
}

I have a SQLGrammarException: Could not load an entity A

If I take a look at the sql generated, I can see that the JOIN is not done and that the inverseColumn column is used in the select clause:

Code:

select
        ...
        b0_.[color=red]B_I[/color]D as B2_24_0_ 
    from
        B b0_ 
....

This means that the joinTable annotation is ignored and Hibernate thinks that an entity A is linked to an entiy B via the foreign key B_ID.....

I do not understand where is the mistake in my mapping.......

Thanks for your help,
tiggy

emmanuel · **Posted:** Wed Oct 25, 2006 12:05 pm

I think I made a comment in the doc about bidir indexed collections, and it is for usre in the Hibernate Core reference documentation, have a look

tiggy · **Joined:** Fri Oct 06, 2006 2:49 am **Posts:** 25

Thx a lot for your help.

I think you pointed out the problem !

I am gonna try this tomorrow and see if it works... I hope it ;)

tiggy · **Joined:** Fri Oct 06, 2006 2:49 am **Posts:** 25

I have first tried to change the type of the collection from a List to a set and apparently my "first" problem does not come from the fact that the collection is indexed.

I thought the Join wa not generated but I made a mistake, the sql generated was for another property which linked also those table but without a joinTable !

I have isolated better the code and I can see that the JOIN is done but there is a foreign_key in my select clause which is not correct:

Code:

select
        a_b_.A_ID,
        a_b_.B_ID,
        a_.id,
        a_.validFrom,
        a_.validTo,
        a_.archivedAt,
        a_.optlock,
        a_.A_ID   <= here is my problem
    from
        A_B a_b_ 
    left outer join
        A a_ on a_b_.B_ID=a_.id 
    where
        a_b_.A_ID=?

If you take a look at the sql generated, you can see that Hibernate assumes that I have a foreign key named A_ID at the many side. I do not understand why a foreign key in the table A is assumed...

Any ideas where is the problem ?

any help is welcome,

tiggy

emmanuel · **Posted:** Tue Nov 07, 2006 5:57 pm

I do have a working test case covering that so either you do something wrong or you use an old HA version