Two one-to-one relationship to the same table

flash.pac · **Joined:** Thu Dec 11, 2003 12:10 pm **Posts:** 16

I have 3 classes.
Account, LimitedAccount and Application
LimitedAccount extends Account and only overwrite some methods.

and all classes are stored using hibernate

My mappings:

Code:

<class name="nl.strohalm.cyclos.entities.accounts.IAccountOwner" table="members">
        <id name="id" type="long" column="member_id">
            <generator class="native"/>
        </id>
        <discriminator column="subclass" type="string"/>
        
    <subclass name="nl.strohalm.cyclos.entities.application.Application">
        <one-to-one name="bankAccount"/>
        <one-to-one name="communityAccount"/>
    </subclass>
</class>

Code:

<class name="nl.strohalm.cyclos.entities.accounts.Account" table="accounts">
      <id name="id" type="long" column="account_id">
            <generator class="native"/>
      </id>
      <discriminator column="subclass" type="string"/>
      <property name="creationDate" column="creationDate" type="calendar"/>
      <property name="lastAmount" column="lastAmount" type="float"/>
      
      <many-to-one name="owner" column="owner_id" class="nl.strohalm.cyclos.entities.accounts.IAccountOwner"/>   
      
      <subclass name="nl.strohalm.cyclos.entities.accounts.LimitedAccount"/>
</class>

If I put 'property-ref="owner"' in one-to-one relationships Hibernate can't find protected property owner into LimitedAccount although this class extends Account!!!

When I load the application instance I get this exception:

Code:

net.sf.hibernate.WrongClassException: Object with id: 1 was not of the specified subclass: nl.strohalm.cyclos.entities.accounts.LimitedAccount (loaded object was of wrong class)

Reading the forum I find some soluctions as "lightweight class pattern" in others....
but these don't solve my problem!!

My question is: Can't I have 2 one-to-one relationships to inherited classes mapped in the same table????

michael · **Posted:** Wed Mar 03, 2004 3:38 pm

Try explicitly mapping the types of the associations.

flash.pac · **Joined:** Thu Dec 11, 2003 12:10 pm **Posts:** 16

Sorry!!

Code:

<class name="nl.strohalm.cyclos.entities.accounts.IAccountOwner" table="members">
        <id name="id" type="long" column="member_id">
            <generator class="native"/>
        </id>
        <discriminator column="subclass" type="string"/>
       
    <subclass name="nl.strohalm.cyclos.entities.application.Application">
        <one-to-one name="bankAccount" class="nl.strohalm.cyclos.entities.accounts.Account"/>
        <one-to-one name="communityAccount" class="nl.strohalm.cyclos.entities.accounts.LimitedAccount"/>
    </subclass>
</class>

michael · **Posted:** Wed Mar 03, 2004 3:49 pm

Does not change anything? Please show the stacktrace and log ... the relations in the database are set up correctly (all fks match etc)?

flash.pac · **Joined:** Thu Dec 11, 2003 12:10 pm **Posts:** 16

My complete stack Trace!!

Code:

net.sf.hibernate.WrongClassException: Object with id: 1 was not of the specified subclass: nl.strohalm.cyclos.entities.accounts.LimitedAccount (loaded object was of wrong class)
   at net.sf.hibernate.loader.Loader.instanceAlreadyLoaded(Loader.java:456)
   at net.sf.hibernate.loader.Loader.getRow(Loader.java:423)
   at net.sf.hibernate.loader.Loader.doQuery(Loader.java:209)
   at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:133)
   at net.sf.hibernate.loader.Loader.doList(Loader.java:950)
   at net.sf.hibernate.loader.Loader.list(Loader.java:941)
   at net.sf.hibernate.loader.CriteriaLoader.list(CriteriaLoader.java:118)
   at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:3571)
   at net.sf.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:223)

All relations in the database are seted up correctly!!

In log this is my query:

Code:

Hibernate: select this.member_id as member_id7_, account1_.account_id as account_id0_, account1_.subclass as subclass0_, account1_.creationDate as creation3_0_, account1_.lastAmount as lastAmount0_, account1_.owner_id as owner_id0_, account2_.account_id as account_id1_, account2_.subclass as subclass1_, account2_.creationDate as creation3_1_, account2_.lastAmount as lastAmount1_, account2_.owner_id as owner_id1_, iaccountow3_.member_id as member_id2_, iaccountow3_.subclass as subclass2_, iaccountow3_.postalCode as postalCode2_, iaccountow3_.telephone1 as telephone12_, iaccountow3_.telephone2 as telephone22_, iaccountow3_.city as city2_, iaccountow3_.email as email2_, iaccountow3_.address as address2_, iaccountow3_.firstName as firstName2_, iaccountow3_.lastName as lastName2_, iaccountow3_.enabled as enabled2_, iaccountow3_.creationDate as creatio12_2_, iaccountow3_.group_admin_id as group_a13_2_, iaccountow3_.province as province2_, iaccountow3_.hideAddress as hideAdd15_2_, iaccountow3_.hideBirthday as hideBir16_2_, iaccountow3_.hideGender as hideGender2_, iaccountow3_.hidePostalCode as hidePos18_2_, iaccountow3_.hideTelephone1 as hideTel19_2_, iaccountow3_.hideTelephone2 as hideTel20_2_, iaccountow3_.hideFax as hideFax2_, iaccountow3_.url as url2_, iaccountow3_.fax as fax2_, iaccountow3_.keywords as keywords2_, iaccountow3_.gender as gender2_, iaccountow3_.birthDay as birthDay2_, iaccountow3_.group_member_id as group_m27_2_, iaccountow3_.area_id as area_id2_, groupadmin4_.group_id as group_id3_, groupadmin4_.name as name3_, groupmembe5_.group_id as group_id4_, groupmembe5_.name as name4_, area6_.area_id as area_id5_, area6_.name as name5_, limitedacc7_.account_id as account_id6_, limitedacc7_.creationDate as creation3_6_, limitedacc7_.lastAmount as lastAmount6_, limitedacc7_.owner_id as owner_id6_ from members this left outer join accounts account1_ on this.member_id=account1_.owner_id left outer join accounts account2_ on account1_.account_id=account2_.account_id left outer join members iaccountow3_ on account2_.owner_id=iaccountow3_.member_id left outer join groups groupadmin4_ on iaccountow3_.group_admin_id=groupadmin4_.group_id left outer join groups groupmembe5_ on iaccountow3_.group_member_id=groupmembe5_.group_id left outer join areas area6_ on iaccountow3_.area_id=area6_.area_id left outer join accounts limitedacc7_ on this.member_id=limitedacc7_.account_id where 1=1 and this.subclass='nl.strohalm.cyclos.entities.application.Application'

No more entries in log becouse this is the first select of application!!

michael · **Posted:** Wed Mar 03, 2004 4:26 pm

Are you sure the fk in communityAccount does not refer to a row which is a Account?

flash.pac · **Joined:** Thu Dec 11, 2003 12:10 pm **Posts:** 16

Yes, I'm sure becouse communityAccount is a LimitedAccount instance

In Application class:

Code:

private Account bankAccount;
private LimitedAccount communityAccount;

With related getters and setters!

michael · **Posted:** Wed Mar 03, 2004 4:45 pm

Please check the row with id 1 in the accounts table, is there really the discriminator for LimitedAccount in the "subclass" column?

flash.pac · **Joined:** Thu Dec 11, 2003 12:10 pm **Posts:** 16

No becouse the row with id = 1 is the bankAccount with subclass = Account

Code:

+------------+-----------------------------------------------------+---------------------+------------+----------+
| account_id | subclass                                            | creationDate        | lastAmount | owner_id |
+------------+-----------------------------------------------------+---------------------+------------+----------+
|          1 | nl.strohalm.cyclos.entities.accounts.Account        | 2004-03-03 16:19:10 |          0 |        1 |
|          2 | nl.strohalm.cyclos.entities.accounts.LimitedAccount | 2004-03-03 16:19:10 |          0 |        1 |

michael · **Posted:** Wed Mar 03, 2004 5:17 pm

I really suspect the association is messed up. Please show the record in the other table

flash.pac · **Joined:** Thu Dec 11, 2003 12:10 pm **Posts:** 16

This is the only row with subclass = Application

Code:

mysql> select member_id, subclass from members;
+-----------+-----------------------------------------------------+
| member_id | subclass                                            |
+-----------+-----------------------------------------------------+
|         1 | nl.strohalm.cyclos.entities.application.Application |

emmanuel · **Posted:** Fri Mar 05, 2004 4:18 am

Object with id 1was not of the specified subclass: nl.strohalm.cyclos.entities.accounts.LimitedAccount

and
1 | nl.strohalm.cyclos.entities.accounts.Account

This is expected.

Should be
1 | nl.strohalm.cyclos.entities.accounts.LimitedAccount

flash.pac · **Joined:** Thu Dec 11, 2003 12:10 pm **Posts:** 16

Ok, I just agree this!!

To solve this problem I tryed to use property-ref in one-to-one relations,
but I get other problem:

Please read my other thread in forum:
http://forum.hibernate.org/viewtopic.php?t=928645