AW: [Objectbridge-developers] Automated deletion of depending obj ects

[Mahler T. <tho...@it...>]

Hi Rainer,

You have to use ODMG Collections to have proper registration of your =
objects
to transaction.

in DListImpl the removing of elemnts is implemented as follows:

	public Object remove(int index)
	{
		DListEntry entry =3D (DListEntry) elements.get(index);
		TransactionImpl tx =3D  getCurrentTransaction();
		tx.markDelete(entry);

		return entry.getRealSubject();
	}

HTH,

-- Thomas


> -----Urspr=FCngliche Nachricht-----
> Von: Bischof, Rainer [mailto:rai...@ed...]
> Gesendet: Mittwoch, 26. September 2001 09:21
> An: obj...@li...
> Betreff: RE: [Objectbridge-developers] Automated deletion of =
depending
> obj ects
> Wichtigkeit: Hoch
>=20
>=20
> Thanks for your answer Thomas!=20
> I had already seen this in the FAQ and I am using the ODMG=20
> interface. But it
> is not clear to me whether I have to use ODMG collections=20
> (DList, etc) or a
> normal Vector.
> That's all.
>=20
> Thanks
>=20
>=20
>=20
> Rainer Bischof
>=20
>=20
> > -----Original Message-----
> > From: Mahler Thomas [mailto:tho...@it...]
> > Sent: Dienstag, 25. September 2001 17:04
> > To: Bischof, Rainer; =
'obj...@li...'
> > Subject: AW: [Objectbridge-developers] Automated deletion=20
> of depending
> > obj ects
> >=20
> >=20
> > Hi Rainer,
> >=20
> > > -----Urspr=FCngliche Nachricht-----
> > > Von: Bischof, Rainer [mailto:rai...@ed...]
> > > Gesendet: Dienstag, 25. September 2001 16:53
> > > An: 'obj...@li...'
> > > Betreff: [Objectbridge-developers] Automated deletion of =
depending
> > > objects
> > > Wichtigkeit: Hoch
> > >=20
> > >=20
> > > Hi Thomas,
> > >=20
> > > somewhere I have read that OJB supports automated deletion of=20
> > > depending
> > > objects in a 1-m relationship. The question is: how do I do that?
> > >=20
> > > I have an object which contains a Vector of depending=20
> > > objects. I want to
> > > delete one of these. So I just open a transaction, get a=20
> > > handle to the main
> > > object and remove one of the depending objects from the Vector. =
On
> > > transaction submit I would expect that OJB removes the=20
> > > corresponding row in
> > > the table.
> > >=20
> > > This does not happen for me ;-(
> > > Mapping has "true" entries for automated retrieval, update=20
> > > and delete. Do I
> > > need to use an ODMG collection instead of the Vector?
> > >=20
> >=20
> > Yes, you need object level transactions that come only with ODMG !
> >=20
> > See excerpt from the FAQ:
> >=20
> > Say you use the PB to query an object O that has a collection=20
> > attribute col
> > with five elements a,b,c,d,e. Next you delete Objects d and e=20
> > from col and
> > store O again with PersistenceBroker.store(O);
> > PB will store the remaining objects a,b,c. But it will NOT=20
> > delete d and e !
> > If you then requery object O it will again contain a,b,c,d,e !!!=20
> > The PB keeps no transactional state of the persistent=20
> > Objects, thus it does
> > not know that d and e have to be deleted. (as a side note:=20
> > deletion of d and
> > e could also be an error, as there might be references to=20
> > them from other
> > objects !!!)
> > Using ODMG for the above scenario will eliminate all trouble:=20
> > Objects are
> > registered to a transaction so that on commit of the=20
> > transaction it knows
> > that d and e do not longer belong to the collection. the ODMG=20
> > collection
> > will not delete the objects d and e but only the REFERENCES from =
the
> > collection to those objects!
> >=20
> >=20
> > > Thanks
> > > Rainer
> > >=20
> > >=20
> > > _______________________________________________
> > > Objectbridge-developers mailing list
> > > Obj...@li...
> > >=20
https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
> >=20
>=20
>=20

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