AW: [Objectbridge-developers] Querying databases (including local transactions changes)

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

Hi again,

> -----Urspr=FCngliche Nachricht-----
> Von: Geir Ove Gr=F8nmo [mailto:gr...@on...]
> Gesendet: Freitag, 10. August 2001 10:27
> An: obj...@li...
> Betreff: Re: [Objectbridge-developers] Querying databases (including
> local transactions changes)
>=20
>=20
> * Geir Ove Gr=F8nmo
> | It does also not have support for something like a=20
> savepoint where the
> | changes up till the current point in the transaction is actually
> | stored in the database without the transaction being commited. This
> | would allow the query results to be conformed automatically by the
> | database.
> |=20
> | I guess savepoint would also be the most efficient way of =
supporting
> | such a feature - at least if there were support to actually=20
> only store
> | modifications that are relevant to the query you've about to
> | execute. In TopLink this is often not very efficient, since=20
> it is very
> | hard upfront knowing how to store the changes to=20
> efficiently sync the
> | database result with the inmemory-result.
> |=20
> | Does ObjectBridge have support for conforming queries=20
> either in-memory
> | or in the database via savepoints?
>=20
> Being able to just save individual objects (not necessarily all
> transaction changes) in the database should be sufficient for=20
> my current
> needs.
>=20
> PersistenceBroker.savepoint() or PersistenceBroker.save(Object =
object)
> would be fine. :)

The PersistenceBroker.store(object) method works in two modi:
1. No call to PersistenceBroker.beginTransaction() has been made (i.e.
connection.autoCommit =3D true).
Then all store() Operations are directly written to the DB AND =
commited.
2. PersistenceBroker.beginTransaction() has been called.
Then the database inserts and updates are excecuted, but commit is done =
only
on a subsequent call to PersistenceBroker.commitTransaction()

I'm planning to have a special operation
likePersistenceBroker.storeImmediate(object) that ignores all =
transactions
and directly commits it's operations. I will need this feature for a
database lock handling (I want to maintain a table that keeps track of
transactional locks on objects.) If you urgently need this I could try =
to
code a bit faster :-)

cheers

Thomas

>=20
> Does PersistenceBroker.store(Object object) actually do this? The
> javadoc is somewhat unclear on whether the database is modified or =
not
> when this method is called. Are related objects also stored=20
> when calling
> this method?
>=20
> Geir O.
>=20
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>=20