"property-ref" for "key-many-to-one" tag

HeikoB · **Joined:** Thu May 04, 2006 3:44 am **Posts:** 2

Hi,
I am working with a database which structure I cannot change. The database scheme is a little bit "strange":
I've got 2 tables with a one-to-many connection. Both tables have composite-ids. However, just a part of the composite-id of the parent-table is part of the composite-id of the child-table. The rest of the key is not referenced at all.

Code:

=table A=       =table B=
_pk1     <--    _pk1
_pk2            _pk3
more_attr       more_attr

I do not have to care about inconsistences, because _pk3 is just a primary key for history-reasons. Is it possible to model this in hibernate? I am looking for something like "property-ref" for the key-many-to-one tag which of course make no sense in general but in my case.

Thanks a lot for your help!
Greeting, Heiko

LaLiLuna · **Posted:** Wed May 17, 2006 7:23 am

If pk_3 is not in use, you might simply ignore it and treat it as normal property.

Best Regards

Sebastian

HeikoB · **Joined:** Thu May 04, 2006 3:44 am **Posts:** 2

What do you mean with ignore? I do have to map it in class A, right? This is my mapping, which results (of course) in the following error:

Code:

Initial SessionFactory creation failed.org.hibernate.MappingException: Foreign key (...) must have same number of columns as the referenced primary key (...)

Code:

<hibernate-mapping>
    <class name="A" table="a">
        <composite-id name="id" class="AId">
            <key-many-to-one name="pk1" column="pk_1" />
            <key-property name="pk2" type="timestamp">
                <column name="pk_2" length="26" />
            </key-property>
        </composite-id>
...
    </class>
</hibernate-mapping>


<hibernate-mapping>
    <class name="B" table="b">
        <composite-id name="id" class="BId">
            <key-property name="pk1" type="int">
                <column name="pk_1" />
            </key-property>
            <key-property name="pk3" type="timestamp">
                <column name="pk_3" length="26" />
            </key-property>
        </composite-id>
...
    </class>
</hibernate-mapping>

bkmr_77 · **Joined:** Tue Apr 25, 2006 12:04 pm **Posts:** 260

check these mappings

Code:

<hibernate-mapping> 
    <class name="A" table="a"> 
        <composite-id name="id" class="AId"> 
            <key-property name="pk1" column="pk_1" /> 
            <key-property name="pk2" type="timestamp"> 
                <column name="pk_2" length="26" /> 
            </key-property> 
        </composite-id> 

   <many-to-one name="classBObject" column="pk_1" class="B" insert="false" update="false"/>
... 
    </class> 
</hibernate-mapping> 


<hibernate-mapping> 
    <class name="B" table="b"> 
        <composite-id name="id" class="BId"> 
            <key-property name="pk1" type="int"> 
                <column name="pk_1" /> 
            </key-property> 
            <key-property name="pk3" type="timestamp"> 
                <column name="pk_3" length="26" /> 
            </key-property> 
        </composite-id> 
... 
    </class> 
</hibernate-mapping> 

LaLiLuna · **Posted:** Wed May 17, 2006 5:04 pm

ignore means do not use it as key property but simply as a property. You must of course do this on both sides.

Best Regards

Sebastian