Re: [eclipselink-users] JPQL does not do cascading delete

[Warren Tang <warren.c.tang@xxxxxxxxx>]

Thank you! I think I'll stick to JPA for now, and improve it later if 
necessary.

Regards,
Warren Tang <http://blog.tangcs.com>


On Friday, October 14, 2011 1:05:19 AM, Tom Ware wrote:
> Within the confines of the JPA spec, your two options are the ones you
> have likely already discovered.
>
> 1. Read the objects and delete them individually (by iterating, for
> instance)
>
> 2. Run a set of Delete and Update queries to fix relationships
>
> EclipseLink provides some other options
>
> 1. You can enable cascading at the database level if your database
> permits it and tell EclipseLink about it and EclipseLink will handle that
>
> 2. We have some EclipseLink specific APIs that will delete collections
> of objects (however for the most part, these just do the iteration for
> you)
>
> 3. EclipseLink allows stored procedure calls.  You could do your
> deletes in a stored procedure.
>
> -Tom
>
> On 13/10/2011 12:04 PM, Warren Tang wrote:
> > Hi, Tom
> >
> > Thanks for the info.
> >
> > I think I can iterate through each record and delete one by one, but the
> > performance is a big concern.
> >
> > Are there other options? I'm a JPA beginner so I would really
> > appreciate it if
> > you could elaborate.
> >
> > Regards,
> > Warren Tang <http://blog.tangcs.com>
> >
> > On 10/13/2011 11:44 PM, Tom Ware wrote:
> > > Hi,
> > >
> > > From the JPA spec:
> > >
> > > "A delete operation only applies to entities of the specified class
> > > and its
> > > subclasses. It does not cascade to
> > > related entities."
> > >
> > > And:
> > >
> > > "Bulk update maps directly to a database update operation, bypassing
> > > optimistic locking checks. Portable
> > > applications must manually update the value of the version column,
> > > if desired,
> > > and/or manually validate
> > > the value of the version column."
> > >
> > > Bottom line, you have to manage relationships and locking when you
> > > using bulk
> > > delete. The reason is that in order for us to manage relationships,
> > > we have to
> > > have read the entities already and know what the relationships are.
> > > This
> > > statement goes directly to the DB and may delete entities that have
> > > not been
> > > read.
> > >
> > > -Tom
> > >
> > > On 13/10/2011 11:39 AM, Warren Tang wrote:
> > > > t does not do cascading de
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> >
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