Re: [Hibernate] Looking for Volunteers

[Jon L. <jon...@xe...>]

Ok, I'll start looking at it...  It might take me a day or two to complete
it due to things that are going on here at work...

If I have any questions, I'll be sure to ask...

Jon...

----- Original Message -----
From: "Gavin King" <ga...@ap...>
To: "Jon Lipsky" <jon...@xe...>
Cc: <hib...@li...>
Sent: Friday, October 11, 2002 9:27 AM
Subject: Re: [Hibernate] Looking for Volunteers


> I'm pre-warning you that this will be a bit involved, Jon - and you will
> probably have to change the Loadable interface, refactoring some stuff
thats
> currently done in the Loader hierarchy onto the XXXXEntityPersister
classes.
>
> I don't have an existing testcase, but if you add a many-to-one
association
> to some class in Multi.hbm.xml, that will be enough.
>
> MultiTableEntityPersister implements table-per-subclass persistence.
> EntityPersister implements the old-style persistence.
>
> Currently MultiTableEntityPersister is a valid implementation of
operations
> from ClassPersister and Queryable but *not* of all operations defined on
> Loadable. ie. MultiTableEntityPersister defines the operations needed by
> SimpleEntityLoader but not by OuterJoinLoader.
>
> At the moment, I am generating SQL along the lines of:
>
> select
>     t.id as id1, t.clazz as clazz1, t.prop as prop1,
>     t1.subprop as subprop1
> from roottable t
> left outer join subtable t1
> on t.id = t1.id
>
> for the _query_ stuff. That will have to change in a couple of ways:
>
> (1) it doesn't handle the case of two columns with the same name in
> different tables
> (2) it shouldnt always be an outerjoin really .... sometimes it should be
> just a join
>
> but thats enough to get us started. Baby steps. So if you generate
something
> similar for outerjoin loading, we will be in business.
>
> P.S. I just noticed that because MultiTableEntityPersister doesn't support
> outerjoin loading, it also can't be loaded by CollectionLoader or
> EntityLoader. So this is an important thing to finish.
>
>
> ----- Original Message -----
> From: "Jon Lipsky" <jon...@xe...>
> To: "Gavin King" <ga...@ap...>
> Sent: Friday, October 11, 2002 4:34 PM
> Subject: Re: [Hibernate] Looking for Volunteers
>
>
> > Hi Gavin,
> >
> > Not a problem.  If you can point me to a valid test case for this, I'd
be
> > more than willing to make sure the outer join fetching works.
> >
> > Jon...
> >
> >
> > ----- Original Message -----
> > From: "Gavin King" <ga...@ap...>
> > To: <hib...@li...>
> > Sent: Wednesday, October 09, 2002 6:56 PM
> > Subject: [Hibernate] Looking for Volunteers
> >
> >
> > > Okay, I finally have something concrete for normalized
> > (table-per-subclass)
> > > mappings. I went down a couple of wrong paths before I decided on the
> best
> > > approach (a completely new implementation of ClassPersister).
> > >
> > > I can save/load/update/delete instances already.
> > >
> > > We need (in order of importance):
> > >
> > > * SchemaExport support (and proper support in the mapping document)
> > > * Query language integration (the hard bit)
> > > * Support for outerjoin fetching
> > > * Support for versioning (easy)
> > > * support for native id-generation (not very hard)
> > >
> > > If anyone wants to help out with any of these problems, I would very
> much
> > > appreciate it.
> > >
> > > ( In particular, since Jon Lipsky understands the outerjoin fetching
> code,
> > > maybe he would have a look at that stuff? )
> > >
> > > I'm perhaps being slightly over-eager here, since I still need to
rework
> > the
> > > map package part of this; what I've got there now is kludge. But I
will
> do
> > > that (and finish it) tomorrow. When I do that, it will knock the top
> item
> > > off the list by side-effect and make the other items doable.
> > >
> > > Anyway, if anyone can spare the time, please stick your hand up and I
> will
> > > point in right direction....
> > >
> > > Gavin
> > >
> > >
> > >
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