hello everyone,
I'm quite new to Hibernate and I'm currently stuck on trying to achieve something that apears to be rather simple:
I can successfully get a bidirectional relationship between different kinds of objects but not when it involves 'joined-subclasses'.
Here is a description of the setup.
On one end I have 3 concrete classes (called classAAA, classAAB, classAAC). All of them inherit from an abstract class called classAA. And classAA inherits from the interface classA.
On the other end I have another concrete class, called classD. And classAA and classD perform a specific relationship and are bound together (through a many-to-many relationship).
Here are the hibernate mappings:
classA.hbm.xml
Code:
<hibernate-mapping>
<!-- interface class classA -->
<class name="domain.classA" table="classA" abstract="true">
<id column="id" name="id">
<generator class="assigned"/>
</id>
<!-- children of class classA -->
<!-- abstract class classAA -->
<joined-subclass name="domain.classAA" table="classAA" abstract="true">
<key column="id"/>
<set cascade="all" lazy="true" name="classDs" table="classAclassD">
<key column="classAid"/>
<many-to-many class="domain.classD" column="classDid"/>
</set>
<!-- children of classAA -->
<!-- concrete classes -->
<joined-subclass name="domain.classAAA" table="classAAA">
<key column="id"/>
</joined-subclass>
<joined-subclass name="domain.classAAB" table="classAAB">
<key column="id"/>
</joined-subclass>
<joined-subclass name="domain.classAAC" table="classAAC">
<key column="id"/>
</joined-subclass>
</joined-subclass>
</class>
</hibernate-mapping>
classD.hbm.xml
Code:
<hibernate-mapping>
<class name="domain.classD" table="classD">
<id column="label" name="label">
<generator class="assigned"/>
</id>
<set cascade="all" lazy="true" name="classAs" table="classAclassD">
<key column="classDid"/>
<many-to-many class="domain.classAA" column="classAid"/>
</set>
</class>
</hibernate-mapping>
The SQL produced looks funky and is not valid when I try to gather all objects classAA linked to an object of classD when this portion is meant to be resolved:
Code:
<set cascade="all" lazy="true" name="classAs" table="classAclassD">
<key column="classDid"/>
<many-to-many class="domain.classAA" column="classAid"/>
</set>
Code:
select
classAs0_.classDid as classDid1_,
classAs0_.classAid as classAid1_,
classAA1_.id as id7_0_,
case
when classAA1_2_.id is not null then 2
when classAA1_3_.id is not null then 3
when classAA1_4_.id is not null then 4
when classAA1_.id is not null then 1
end as clazz_0_
from
classAclassD classAs0_
left outer join
classAA classAA1_
on classAs0_.classAid=classAA1_.id
left outer join
classA classAA1_1_
on classAA1_.id=classAA1_1_.id left outer join
classAAA classAA1_2_
on classAA1_.id=classAA1_2_.id
left outer join
classAAB classAA1_3_
on classAA1_.id=classAA1_3_.id
left outer join
classAAC classAA1_4_
on classAA1_.id=classAA1_4_.id
where
classAs0_.classDid=?
this section of the SQL code:
Code:
left outer join
classA classAA1_1_
on classAA1_.id=classAA1_1_.id
is the culprit and shouldn't be present.
It is worth noting that also tried to access the superclass classA (and not classAA) from within classD and changed this:
Code:
<many-to-many class="domain.classAA" column="classAid"/>
into that:
Code:
<many-to-many class="domain.classA" column="classAid"/>
but the SQL is still invalid with the same unwanted section.
Can you please help understanding what's happening? I'd be glad if I can get a helping hand on this matter because I really don't understand why it cannot work that way.
Thanks in advance.
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