I have abstract class A and its 2 concrete subclasses ASub1 and ASub2. There is another class B associated with A.
If the association is bidirectional, then we can use <any> or <many-to-any> tag in B.hbm.xml
But what will be the mapping if the association is unidirectional from A to B???
Please help me with this. It's urgent.
Thanks in advance.

Do you mean that A simply have collection of Bs? or simply references B?

Than just use many-to-one
http://www.hibernate.org/hib_docs/v3/re ... -manytoone
Or one of collection tags on a.hbm.xml

[img]D:\inheritance.JPG[/img]

abstract class A
class ASub1 extends A
class ASub2 extends A
class B

A__1___________________________________0..*__B


If the association between abstract class A and B is bidirectional, then the mapping will be as follows
<hibernate-mapping package="many2one">
<class table="B" name="B">
<id type="java.lang.Long" column="ID" name="id">
<generator class="increment"/>
</id>
<any name="A" meta-type="string" id-type="java.lang.Long">
<meta-value class="ASub1" value=" ASub1"/>
<meta-value class="ASub2" value=" ASub2"/>
<column name="A_CLASSNAME"/>
<column name="A_ID"/>
</any>
</class>
</hibernate-mapping>

<hibernate-mapping package="many2one">
<class table="ASub1" name="ASub1">
<id type="java.lang.Long" column="ID" name="id">
<generator class="increment"/>
</id>
<set inverse="true" name="bs">
<key column="A_ID"/>
<one-to-many class="B"/>
</set>
</class>
</hibernate-mapping>

<hibernate-mapping package="many2one">
<class table="ASub2" name="ASub2">
<id type="java.lang.Long" column="ID" name="id">
<generator class="increment"/>
</id>
<set inverse="true" name="bs">
<key column="A_ID"/>
<one-to-many class="B"/>
</set>
</class>
</hibernate-mapping>

But if the association between abstract class A and B is unidirectional from A to B, then we can’t specify <any> tag in B.hbm.xml. foreign key column “A_ID” can be specified in the ASub1.hbm.xml and ASub2.hbm.xml. But there is no place where we can specify column “A_CLASSNAME”.

how to map this in case of unidirectional association with tabla per concrete class?