Batch Delete in Hibernate

[Saket Barve]

I did some groundwork on batch deletes in Hibernate and came across a useful link at Aaron Johnson's blog.

I implemented the suggestion in the following manner:

    
 
                StringBuffer itemIdsForDelete = new StringBuffer();
// Convert the IDs into CSV format
for( Iterator iter = pomItemIds.iterator(); iter.hasNext(); )               {
itemIdsForDelete.append( iter.next() );
if( iter.hasNext() ) {
itemIdsForDelete.append( " , " );
} 
} 
 
 
// Form the queries
StringBuffer delItmValQry = new StringBuffer( " select pigv from Pomitemgradeval pigv " );
delItmValQry.append( " where pigv.id.pomItemId IN ( " + itemIdsForDelete.toString() + " ) " );

StringBuffer delItemsQry = new StringBuffer( " select pi from Pomitem pi " );
delItemsQry.append( " where pi.pomItemId IN ( " + itemIdsForDelete.toString() + " ) " );

Session session = getCurrentSession();
Query query = session.createQuery( delItmValQry.toString() );

// Step 1: Delete all the gradevals associated with the itemid
session.delete( delItmValQry.toString() );

// Step 2: Delete all the items 
session.delete( delItemsQry.toString() );
 

Upon implementing the given suggestion as shown above, following MappingException results:

   
 
[5/13/07 12:59:02:623 EDT] 00000011 ExceptionUtil E   CNTR0020E: EJB threw an unexpected (non-declared) exception during invocation of method "saveAndUpdateGradeData" on bean "BeanId(StrideServiceEar#StrideService.jar#POMGradeService, null)". Exception data: org.hibernate.MappingException: Unknown entity: java.lang.String
at org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java(Compiled Code))
at org.hibernate.impl.SessionImpl.getEntityPersister(SessionImpl.java:1338)
at org.hibernate.event.def.DefaultDeleteEventListener.onDelete(DefaultDeleteEventListener.java:78)
at org.hibernate.event.def.DefaultDeleteEventListener.onDelete(DefaultDeleteEventListener.java:52)
at org.hibernate.impl.SessionImpl.fireDelete(SessionImpl.java:766)
at org.hibernate.impl.SessionImpl.delete(SessionImpl.java:744)
 

It appears that the session's delete method is not able to make sense of the query passed as a string.

Can anyone tell me what I am doing wrong? Or, is there is another way to go about this mass delete thing?

Thanks,
Saket
[ May 13, 2007: Message edited by: Saket Barve ]

[Jaikiran Pai]

The Hibernate documentation mentions that this method has been deprecated.

Deprecated. consider using HQL delete statements

Delete all objects returned by the query. Return the number of objects deleted.

Note that this is very different from the delete-statement support added in HQL since 3.1. The functionality here is to actually peform the query and then iterate the results calling Session.delete(Object) individually.

Moreover, this method is available on org.hibernate.classic.Session object and not org.hibernate.Session

[Saket Barve]

Thanks, Jaikiran.

The solution was to modify the delete query and pass the ID's as a parameter-list.