Hi friends,

I was trying to implement optimistic locking in my APIs where hibernate is the persistence layer. As per the hibernate documents, I have done the version configuration, by adding the <version> tag in the hibernate mapping files. But while running the application, it is showing the following exception, whenever I tried to save a new object to datastore using session.save(object) call.

org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: org.mypackage.Bid

Hibernate version:
Hibernate 3

Mapping documents:
1) Item.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="org.mypackage.Item" table="item" >
<comment></comment>
<id name="PRIMARY_KEY" type="int">
<column name="PRIMARY_KEY" />
<generator class="org.mypackage.MyHibernateIDGenerator" />
</id>
<version name="VERSION" column="VERSION" type="java.lang.Integer" />
<many-to-one name="bid" class="org.mypackage.Bid" fetch="select">
<column name="BID_ID">
<comment></comment>
</column>
</many-to-one>
</class>
</hibernate-mapping>

2) Bid.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="org.mypackage.Bid" table="bid" >
<comment></comment>
<id name="PRIMARY_KEY" type="int">
<column name="PRIMARY_KEY" />
<generator class="org.mypackage.MyHibernateIDGenerator" />
</id>
<version name="VERSION" column="VERSION" type="java.lang.Integer" />
<set name="items" inverse="true">
<key>
<column name="bid_id" not-null="true">
<comment></comment>
</column>
</key>
<one-to-many class="org.mypackage.Item" />
</set>
</class>
</hibernate-mapping>

Code between sessionFactory.openSession() and session.close():
I am using CMP framework.
try
{
Session session = getHibernateSession();
Item i = new Item();
i.setBid( new Bid (bidId) );
session.save(i);
} catch (Exception e){
e.printStackTrace();
}

Full stack trace of any exception that occurs:
org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: org.mypackage.Bid
at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:216)
at org.hibernate.type.EntityType.getIdentifier(EntityType.java:108)
at org.hibernate.type.ManyToOneType.isDirty(ManyToOneType.java:221)
at org.hibernate.type.TypeFactory.findDirty(TypeFactory.java:476)
at org.hibernate.persister.entity.AbstractEntityPersister.findDirty(AbstractEntityPersister.java:2803)
at org.hibernate.event.def.DefaultFlushEntityEventListener.dirtyCheck(DefaultFlushEntityEventListener.java:467)
at org.hibernate.event.def.DefaultFlushEntityEventListener.isUpdateNecessary(DefaultFlushEntityEventListener.java:190)
at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:113)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:195)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:76)
at org.hibernate.event.def.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:35)
at org.hibernate.impl.SessionImpl.autoFlushIfRequired(SessionImpl.java:951)
at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:109)
at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:88)
at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1540)

Name and version of the database you are using:
MySql 5.0.27

The generated SQL (show_sql=true):
No sql generated.

Debug level Hibernate log excerpt:
-

Any helps are most welcome. And thanks in advance.
Manoj.

Hi Manoj,

try adding cascade="all" to your many-to-one mapping.

See http://www.hibernate.org/hib_docs/v3/re ... d-cascades

-Thomas

Hello Thomas,

You are absolutely right, and it worked fine. Thanks alot for your helpful reply.

Manoj.