Обсуждение: Statement level transactions

Hi,

With the introduction of checkpoints, it is now possible (or has been
made very easy) to implement behaviour what Oracle calls "statement
level transaction". E.g:

Inserting an already existing value into a column with unique key
constraint throws an exception, but the containing transaction can
continue. I can mimique this behaviour by using checkpoints.

Is there any facility in place (in the JDBC driver or in the backend)
that already does this for me? I.e. is there a config parameter that I
have just to turn on to have statement level transaction behaviour?

I also remember having read in the new features list for 8.0 the
introduction of nested transaction. I found no mention to nested
transactions in the user guides though. Am I missing something?

Thank you!

Regards,
Peter

On Fri, 25 Feb 2005, [ISO-8859-1] Kovács Péter wrote:

> With the introduction of checkpoints, it is now possible (or has been
> made very easy) to implement behaviour what Oracle calls "statement
> level transaction". E.g:
>
> Inserting an already existing value into a column with unique key
> constraint throws an exception, but the containing transaction can
> continue. I can mimique this behaviour by using checkpoints.
>
> Is there any facility in place (in the JDBC driver or in the backend)
> that already does this for me? I.e. is there a config parameter that I
> have just to turn on to have statement level transaction behaviour?
>
> I also remember having read in the new features list for 8.0 the
> introduction of nested transaction. I found no mention to nested
> transactions in the user guides though. Am I missing something?
>

8.0 has implemented savepoints, which I think you are calling checkpoints.
The driver has no provision for automatically setting and rolling back to
savepoints.  There was some discussion on this list about doing that, and
it was generally agreed it would be a nice compatibility feature for other
databases, but no one has stepped up to do that yet.  For now you can
manually set and release Savepoints with the standard JDBC interface.

Kris Jurka

Hi, Peter,


Kovács Péter schrieb:

> I also remember having read in the new features list for 8.0 the
> introduction of nested transaction. I found no mention to nested
> transactions in the user guides though. Am I missing something?

Savepoints can be used to create nested transactions. For every inner
transaction you want to start, create a savepoint. If you want to commit
or abort that transaction, you release or rollback that savepoint.

Actually, savepoints allow more flexible usage patterns compared to
nested transactions.

HTH,
Markus

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