hibernate - Is "flush" of session must called in this case? -

i defined "booking" entity "part" entity ,their relationship 1 many.now in case had such operation

step 1:retrieve 1 booking fk,assume under booking,it has 3 part,then show in ui

step 2:in ui,i add 1 new part,then mark original 3 saved part deleted part,finally save booking again.

now in back-end,i handle saving logic following

first,my booking action's save function following

       public string save() throws exception{             booking = presave(booking);             booking = dosave(booking);             booking = postsave(booking);             return success;         } 

the dosave function following

@transactional(propagation=propagation.required,isolation=isolation.default)         private booking dosave(booking booking) throws exception{             logger.debug("save booking start,will delete deleted/update/save record in db");             //step 1:get booking dao spring context             bookingdao dao  = (bookingdao) daofactory.getdao("booking");             //step 2:get deleted object booking tree,as usual,the deleted object marked in ui             list tobedeleted = bookingutil.handledeletedobj(booking);              logger.debug("the deleted object ["+tobedeleted+"]");              //step 3:if deleted object not empty,invoke booking dao's delete function delete them              if(tobedeleted!=null && tobedeleted.size()>0){                   dao.delete(tobedeleted);              }              //step 4:invoke booking dao's save function save/update obj             booking = (booking) dao.save(booking);             return booking;         } 

delete function in dao

@override @transactional(propagation=propagation.required,isolation=isolation.default) public object delete(object object) {     // todo auto-generated method stub     logger.debug("delete deleted object ["+object+"]");     if(object == null){         logger.error("there no deleted object found");         return null;     }     session session = sf.opensession();     if(object instanceof  list){         list list = (list) object;         for(object obj:list){             session.delete(obj);         }         //session.flush();         return list;     }     return object; } 

save function in booking dao

@override

@transactional(propagation=propagation.required,isolation=isolation.default)

public object save(object object) {     logger.debug("save() start,save booking["+object+"] db");     booking booking = (booking)object;     string bookingno = null;     //step 1:check if booking no empty,if empty,generate booking no customer first     if(booking.getbookingno() == null || booking.getbookingno().trim().isempty()){         logger.debug("save(),find booking no empty,will generate booking no first");             bookingno = (string) generatebookingno(booking.getcustomer());             //set generated booking no booking             booking.setbookingno(bookingno);     }      //step 2:set part's fk bookingno     list <part>parts = booking.getparts();     if(parts!=null){         for(part part:parts){             if(part.getbookingno() == null || part.getbookingno().isempty()){                 part.setbookingno(booking.getbookingno());             }         }     }     //step 3:set todoitem's fk     list<todoitem>todoitems = booking.gettodoitems();     if(todoitems!=null){         for(todoitem todoitem:todoitems){             if(todoitem.getbookingno() == null  || todoitem.getbookingno().isempty()){                 todoitem.setbookingno(booking.getbookingno());             }         }     }      //step 4:save/update booking     session session = sf.getcurrentsession();     session.saveorupdate(booking);     session.flush();     return booking; } 

as see,my logic quite simple:delete stuff , save stuff,beside point,they should in 1 transaction,but when test,i found after call save action's save(),the parts didn't been deleted @ all,the log following:

17:37:36,143 debug bookingdao:122 - delete deleted object [[com.chailie.booking.model.booking.part@712e3058, com.chailie.booking.model.booking.part@f681b75, com.chailie.booking.model.booking.part@7be2a639]] 17:37:36,144 debug sessionimpl:220 - opened session @ timestamp: 13676602561 17:37:36,147 debug defaultdeleteeventlistener:65 - entity not persistent in delete processing 17:37:36,149 debug versionvalue:44 - version unsaved-value strategy undefined 17:37:36,150 debug identifiervalue:104 - id unsaved-value: null 17:37:36,153 debug defaultdeleteeventlistener:180 - deleting [com.chailie.booking.model.booking.part#2] 17:37:36,154 debug sessionimpl:1308 - setting cache mode to: 17:37:36,155 debug sessionimpl:1308 - setting cache mode to: normal 17:37:36,160 debug sessionimpl:1308 - setting cache mode to: 17:37:36,162 debug sessionimpl:1308 - setting cache mode to: normal 17:37:36,162 debug defaultdeleteeventlistener:65 - entity not persistent in delete processing 17:37:36,163 debug versionvalue:44 - version unsaved-value strategy undefined 17:37:36,163 debug identifiervalue:104 - id unsaved-value: null 17:37:36,164 debug defaultdeleteeventlistener:180 - deleting [com.chailie.booking.model.booking.part#3] 17:37:36,165 debug sessionimpl:1308 - setting cache mode to: 17:37:36,165 debug sessionimpl:1308 - setting cache mode to: normal 17:37:36,166 debug sessionimpl:1308 - setting cache mode to: 17:37:36,166 debug sessionimpl:1308 - setting cache mode to: normal 17:37:36,167 debug defaultdeleteeventlistener:65 - entity not persistent in delete processing 17:37:36,168 debug versionvalue:44 - version unsaved-value strategy undefined 17:37:36,168 debug identifiervalue:104 - id unsaved-value: null 17:37:36,169 debug defaultdeleteeventlistener:180 - deleting [com.chailie.booking.model.booking.part#4] 17:37:36,170 debug sessionimpl:1308 - setting cache mode to: 17:37:36,171 debug sessionimpl:1308 - setting cache mode to: normal 17:37:36,171 debug sessionimpl:1308 - setting cache mode to: 17:37:36,172 debug sessionimpl:1308 - setting cache mode to: normal 17:37:36,173 debug jdbctransaction:103 - commit 17:37:36,174 debug sessionimpl:337 - automatically flushing session 17:37:36,174 debug jdbccontext:201 - before transaction completion 17:37:36,175 debug sessionimpl:393 - before transaction completion 17:37:36,176 debug jdbctransaction:193 - re-enabling autocommit 17:37:36,177 debug jdbctransaction:116 - committed jdbc connection 17:37:36,178 debug jdbccontext:215 - after transaction completion 17:37:36,178 debug connectionmanager:296 - transaction completed on session on_close connection release mode; sure close session release jdbc resources! 17:37:36,179 debug sessionimpl:422 - after transaction completion 17:37:36,179 debug sessionimpl:353 - automatically closing session 17:37:36,180 debug sessionimpl:273 - closing session 17:37:36,180 debug connectionmanager:374 - performing cleanup 17:37:36,181 debug connectionmanager:435 - releasing jdbc connection [ (open preparedstatements: 0, globally: 0) (open resultsets: 0, globally: 0)] 17:37:36,182 debug jdbccontext:215 - after transaction completion 17:37:36,182 debug connectionmanager:296 - transaction completed on session on_close connection release mode; sure close session release jdbc resources! 17:37:36,183 debug sessionimpl:422 - after transaction completion 17:37:36,184 debug sessionimpl:273 - closing session 

but when add session.flush() in end of booking dao's delete(),it delete part in db successful.

so question is: when didn't have flush() in dao's delete function(),why part can't deleted?

ps:my session factory spring configuration following:

bean id="sessionfactory"         class="org.springframework.orm.hibernate3.annotation.annotationsessionfactorybean">         <property name="datasource">             <ref bean="datasource1" />         </property>         <property name="hibernateproperties">              <props>                 <prop key="hibernate.dialect">                     org.hibernate.dialect.mysqldialect                 </prop>                 <prop key="hibernate.show_sql">true</prop>                  <prop key="hibernate.transaction.flush_before_completion">true</prop>                   <prop key="hibernate.transaction.auto_close_session">true</prop>                    <prop key="hibernate.connection.release_mode">auto</prop>                    <prop key="hibernate.hbm2ddl.auto">update</prop>                    <prop key="format_sql">true</prop>             </props>         </property>          <property name="packagestoscan">                <list>                     <value>com.chailie.booking.model.*</value>                 </list>       </property>