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Thread: getting the oid for a new tuple in a BEFORE trigger

getting the oid for a new tuple in a BEFORE trigger

From
Markus Wagner
Date:
Hi,

we need to control database changes within BEFORE triggers.
There is no problem with triggers called by update, but there is
a problem with triggers called by insert.

We strongly need to know the oid of a newly inserted tuple. In this case, we
use tg_newtuple of the TriggerData structure passed to thetrigger function,
and its t_data -> t_oid will have the value '0'.

Using BEFORE and AFTER triggers would make our lives much harder.

Is there any way (even hack) to get the oid the newly inserted tuple will
receive?

Thank you very much,

Markus

Re: getting the oid for a new tuple in a BEFORE trigger

From
"Mikheev, Vadim"
Date:
> we need to control database changes within BEFORE triggers.
> There is no problem with triggers called by update, but there is
> a problem with triggers called by insert.
>
> We strongly need to know the oid of a newly inserted tuple.
> In this case, we use tg_newtuple of the TriggerData structure
> passed to thetrigger function, and its t_data -> t_oid will
> have the value '0'.
>
> Using BEFORE and AFTER triggers would make our lives much harder.
>
> Is there any way (even hack) to get the oid the newly
> inserted tuple will receive?

Just set t_data->t_oid = newoid() - this is what backend does
in heapam.c:heap_insert().

Vadim

Re: [HACKERS] getting the oid for a new tuple in a BEFORE

From
Bruce Momjian
Date:
> > we need to control database changes within BEFORE triggers.
> > There is no problem with triggers called by update, but there is
> > a problem with triggers called by insert.
> >
> > We strongly need to know the oid of a newly inserted tuple.
> > In this case, we use tg_newtuple of the TriggerData structure
> > passed to thetrigger function, and its t_data -> t_oid will
> > have the value '0'.
> >
> > Using BEFORE and AFTER triggers would make our lives much harder.
> >
> > Is there any way (even hack) to get the oid the newly
> > inserted tuple will receive?
>
> Just set t_data->t_oid = newoid() - this is what backend does
> in heapam.c:heap_insert().

Does that work?  Doesn't that get overwritten when the actual INSERT
happens?

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