Hi,

I have a base class User and a sub class SuperUser that are mapped to tables TBL_USER and TBL_SUPER_USER using table per subclass stradegy.
My problem is that I can't find a way to "upgrade" a User object to a SuperUser object. In other words, When a User object already exists in the database, how can I create a row in the TBL_SUPER_USER table that references the existing row in the TBL_USER table?

I can't delete the existing User row and copy it into a new SuperUser object because the existing User row may already been referred in some other tables.

Thanks for any suggestions.

Hibernate version:
2.1.x

Mapping documents:
<?xml version="1.0"?>

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

<hibernate-mapping>
<class
name="User"
table="TBL_USER"
dynamic-update="false"
dynamic-insert="false"
>

<id
name="id"
column="ID"
type="java.lang.Integer"
>
<generator class="hilo">
</generator>
</id>

<property
name="username"
type="java.lang.String"
update="true"
insert="true"
access="property"
column="USERNAME"
length="25"
not-null="true"
/>

<property
name="password"
type="java.lang.String"
update="true"
insert="true"
access="property"
column="PASSWORD"
length="25"
not-null="true"
/>

<joined-subclass
name="SuperUser"
table="TBL_SUPER_USER"
dynamic-update="false"
dynamic-insert="false"
>
<key
column="ID"
/>

<property
name="someProp"
type="java.lang.String"
update="true"
insert="true"
access="property"
column="SOME_PROP"
length="50"
/>

</joined-subclass>

</class>

</hibernate-mapping>


Code between sessionFactory.openSession() and session.close():

Transaction trx = session.beginTransaction();
session.saveOrUpdate(obj);
trx.commit();

Full stack trace of any exception that occurs:

net.sf.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: 98729985, of class: SuperUser
at net.sf.hibernate.impl.SessionImpl.checkUniqueness(SessionImpl.java:1666)
at net.sf.hibernate.impl.SessionImpl.doUpdateMutable(SessionImpl.java:1435)
at net.sf.hibernate.impl.SessionImpl.doUpdate(SessionImpl.java:1462)
at net.sf.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:1385)
at SuperUserDAO.save(SuperUserDAO.java:160)
at UserSaveAction.execute(UserSaveAction.java:175)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at com.crosslink.web.app.filter.OpenSessionInViewFilter.doFilter(OpenSessionInViewFilter.java:45)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2422)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:163)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:199)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:534)

Name and version of the database you are using:
Sql Server 2k

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

you cannot change a type in java --> so it is impossible

the way to do it:
1- get baseObject
2- create new subObject
3- copy all from baseObject to subObject
4- delete baseObject
5- save subObject

Anthony,

I can't simply delete the base object as it is referenced by many other objects.
So I guess I need to save the subObject first? Then is there a easy way to update all other objects that are referencing the old baseObject to reference the new subObject before I delete the old baseObject?

Thank you!

gah. I've run into exactly the same problem. I'm going to have a think about how I designed my app and let you know of any ways that appeal to me.

that's a good point, tell the community how you manage it

Well, I just worked around it by using composition instead of inheritance

yep me too.
I doing something similar to the one-to-one mapping example in the online docs.

I had the same problem...and deletion and re-insert is not a viable option, for many reasons, cascade-delete being the primary.

the solution I opted for is a simple jdbc insert into the joined-subclass table with that foreign-key ( all other columns can be left empty), and then doing the regular update via Hibernate. The existence of that row in the sub-class table will make Hibernate happy.

btw, Hibernate should really be able to handle this automatically, leveraging the Oracle upsert statement... [/quote]