FlushMode.NEVER and session.update problem

martin.d · **Joined:** Thu Feb 24, 2005 5:21 pm **Posts:** 5

Hibernate version: 2.1

Mapping documents:

Parent class:
<class name="ncr.dpc.domain.Promotion" table="PROMOTIONS">
<id name="id" column="promotionId" type="integer" unsaved-value="null">
<generator class="native"/>
</id>
<property name="code" type="integer"/>
<property name="customerEmployeeDiac" type="boolean"/>
<property name="customerNotEmployeeDiac" type="boolean"/>
<property name="customerRecordDiac" type="boolean"/>
<property name="description" type="string"/>
<property name="directed" type="boolean"/>
<property name="instantWin" type="boolean"/>
<property name="instantWinEvaluationMode" type="integer"/>
<property name="instantWinPrizeOddsOfWinning" type="integer"/>
<property name="instantWinPrizeQuantity" type="integer"/>
<property name="instantWinOddsCalculation" type="integer"/>
<property name="endDate" type="date"/>
<property name="endTime" type="string"/>
<property name="offlineDiac" type="integer"/>
<property name="priority" type="integer"/>
<property name="rewardLimitation" type="integer"/>
<property name="rewardLimitationTimes" type="integer"/>
<property name="rewardLimitationTransaction" type="integer"/>
<property name="startDate" type="date"/>
<property name="startTime" type="string"/>
<property name="state" type="integer"/>
<many-to-one name="promotionVariable" column="promotionVariableId" class="ncr.dpc.domain.PromotionVariable"/>
<many-to-one name="originalPromotion" class="ncr.dpc.domain.Promotion" column="originalPromotionId" unique="true"/>
<many-to-one name="category" class="ncr.dpc.domain.PromotionCategory" column="promotionCategoryId"/>
<list name="conditions" cascade="all-delete-orphan" lazy="true" access="field">
<key column="promotionId"/>
<index column="position"/>
<one-to-many class="ncr.dpc.domain.condition.Condition"/>
</list>
</class>

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

This is the method in the persistence layer to initialize a lazy collection

Code:

   public List retrieveConditions(Promotion promotion) throws NCRHomeException {
      Session session =  getSession();
      session.setFlushMode(FlushMode.NEVER);
      Transaction tr;
      try {
         tr = session.beginTransaction();
         session.update(promotion);
         if (!Hibernate.isInitialized(promotion.conditions)) {
            Hibernate.initialize(promotion.conditions);
         }
         tr.rollback();
         return promotion.conditions;
      } catch (HibernateException e) {
         //@TODO Log
         throw new HomeException(e);
      } finally {
         this.closeSession(session);
      }
   }

Name and version of the database you are using:
MySql 4.1.8

The case is that a need to work with the objects over several transactions, only saving it when the user presses the save button. The problem arises when a add a new object to the lazy collection. For some reason, the session.updates() does update the lazy collection, inserting in the db the new objects. But when a remove the cascade attribute, this doesn't happend. It's very useful using the cascade attribute, so I'd like to know if I'm doing something wrong.

Thanks,
Martin.[/quote]

anthony · **Posted:** Fri Feb 25, 2005 4:47 am

what i understand is that you're trying to use long session per application pattern (several httprequest + a global commit).
The good point is that you've notices the need to set flushmode to NEVER.

The bad point is that it seems you're modifying detached instance.
IMO, session per application pattern has to be used when you don't want to manage detached instance.

So, i must recommend you to use session.lock(detachedObject, LockMode.NONE) to associate an unmodified detached instance, then you can change properties if you want and load lazy associations.

Only use session per application pattern if you're able to really define the start and the end of an application transaction. These kind of transaction shouldn't be too long.