I have a base class mapped to a table,

It has two subclasses that have a discriminator on them:

baseclass discriminator="BASE"
subclass1 discriminator="PAY"
subclass2 discriminator="ORDER"


when I call:

session.load(baseclass.class, id);

I get a net.sf.hibernate.WrongClassException: Object with id: 12 was not of the specified subclass.

This is what I expect to happen because the row with id = 12 corresponds to a discriminator of ORDER not BASE.


The problem is that when I call

session.load(subclass1.class, id);

Hibernate will return me a valid instance of subclass1 even though the id I pass in belong to a row on the table where the discriminator column reads ORDER.

Why don't I get the same exception when I use the incorrect subclass?

Thanks,

Marco

Here is my mapping

<class name="com.BaseClass" table="BASE">

<id column="BASE_ID" name="id" type="long">
<generator class="assigned"/>
</id>

<discriminator column="TYPE_CD" type="string" force="true"/>

<property column="DESCRIPTION" name="description" type="string"/>

<subclass name="com.PAY" discriminator-value="PAY">
</subclass>

<subclass name="com.Order" discriminator-value="ORD">
</subclass>
</class>

Please show the detailed exception message. Are you using a recent Hibernate Version?

Here is the detailed exception. But again, it is not the exception that I am concerned about. I expected an exception. I am concerned about the second case in which I recieved no exception even though the discriminator for the class I used in the load method PAY and not ORD.



An exception has been caused by: net.sf.hibernate.WrongClassException: Object with id: 12 was not of the specified subclass: com.kmart.kima.domain.ActivityPointRole (Discriminator: ORD )
net.sf.hibernate.WrongClassException: Object with id: 12 was not of the specified subclass: com.kmart.kima.domain.ActivityPointRole (Discriminator: ORD )
at net.sf.hibernate.loader.Loader.getInstanceClass(Loader.java:576)
at net.sf.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:489)
at net.sf.hibernate.loader.Loader.getRow(Loader.java:421)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:204)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:128)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:826)
at net.sf.hibernate.loader.Loader.loadEntity(Loader.java:846)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:57)
at net.sf.hibernate.loader.EntityLoader.load(EntityLoader.java:49)
at net.sf.hibernate.persister.EntityPersister.load(EntityPersister.java:420)
at net.sf.hibernate.impl.SessionImpl.doLoad(SessionImpl.java:2042)
at net.sf.hibernate.impl.SessionImpl.doLoadByClass(SessionImpl.java:1916)

I know, just wanted to know if I was reading up in the right part of the source :)

I can confirm this. I use following mapping:

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
<class name="Site" table="sites" discriminator-value="not null">
<id name="siteID" unsaved-value="-1">
<column name="site_id" not-null="true" />
<generator class="native">
<param name="sequence">sites_site_id_seq</param>
</generator>
</id>

<discriminator column="status" />

<property name="name" />

<subclass name="ActiveSite" discriminator-value="1" />
</class>
</hibernate-mapping>

When I use query 'from ActiveSite', rows with discrminator set to value other than 1 are not returned. But session.load(ActiveSite.class, new Integer(1)) returns row even if discriminator is set to value other than 1. When I enabled logging with debug level, I can see that discriminator column is neither selected nor used in where. Hibernate uses following SQL query for this mapping when ActiveSite.class instance is requested via session.load method:

select activesite0_.site_id as site_id0_, activesite0_.name as name0_ from sites activesite0_ where activesite0_.site_id=?

I think, it should be something like this:

select activesite0_.site_id as site_id0_, activesite0_.name as name0_, activesite0_.status as status0_ from sites activesite0_ where activesite0_.status=1 and activesite0_.site_id=?

Tested on Hibernate 2.1.1.