<class
        name="com.eaf.model.TemparioPartiDanno"
        table="atm_tempario_parti_danno"
        select-before-update="false"
        dynamic-update="true"
        dynamic-insert="true"
        optimistic-lock="all"
    >
      <id
            name="codTParteDanno"
            column="cod_t_parte_danno"
            type="java.lang.String"
            length="3"
         unsaved-value="undefined"
        >
            <generator class="assigned">
            </generator>
....
    </class>
</hibernate-mapping>

<hibernate-mapping>
    <class
        name="com.eaf.model.AtmFattDettaglioCommesse"
        table="atm_fatt_dettaglio_commesse"
        select-before-update="false"
        dynamic-update="false"
        dynamic-insert="false"
        optimistic-lock="version"
    >
      <id
            name="idFattDettaglioCommesse"
            column="id_fatt_dettaglio_commesse"
            type="java.lang.Integer"
        >
            <generator class="increment">
            </generator>
        </id>
....

      </many-to-one>
    <!-- imported bi-directional many-to-one association to TemparioPartiDanno -->
      <many-to-one
         name="TemparioPartiDanno"
         class="com.eaf.model.TemparioPartiDanno"
            not-null="false"
         outer-join="auto"
      >   
         <column name="cod_t_parte_danno" />
      </many-to-one>

    </class>
</hibernate-mapping>

[eaf] DEBUG [http-8080-Processor24] AtmFattDettaglioCommesseDAOHibernate.saveAtmFattDettaglioCommesse(75) | atmFattDettaglioCommesse's id: 9
[eaf] ERROR [http-8080-Processor24] AbstractFlushingEventListener.performExecutions(277) | Could not synchronize database state with session
org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.eaf.model.TemparioPartiDanno
   at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:216)
   at org.hibernate.type.EntityType.getIdentifier(EntityType.java:99)
   at org.hibernate.type.ManyToOneType.nullSafeSet(ManyToOneType.java:63)
   at org.hibernate.persister.entity.BasicEntityPersister.dehydrate(BasicEntityPersister.java:1617)
   at org.hibernate.persister.entity.BasicEntityPersister.update(BasicEntityPersister.java:1963)
   at org.hibernate.persister.entity.BasicEntityPersister.updateOrInsert(BasicEntityPersister.java:1909)
   at org.hibernate.persister.entity.BasicEntityPersister.update(BasicEntityPersister.java:2149)
   at org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:75)
   at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:239)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:223)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:137)
   at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:274)
   at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)