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Date: Tue, 28 Jun 94 13:20:21 +0200
From: joerg.plewe@mpi-dortmund.mpg.de (J.Plewe)
Message-Id: <9406281120.AA10298@dl.mpi-dortmund.mpg.de>
To: postgres@postgres.Berkeley.EDU
Subject: Re: PQExec inside a C function?
Resent-To: postgres-redist@postgres.Berkeley.EDU
Resent-Date: Tue, 28 Jun 94 04:20:41 -0700
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> bruce@comu11.auckland.ac.nz (Bruce Thomson) writes:
> > I am trying to call a user function from within the monitor that should
> > do some PQExec'd insertions into a table.
> 
> > PQsetdb ("external");
> > PQexec("begin");
>           ^^^^^
> > sprintf(append_line,"append twovals(x1=%d,x2=%d)",x,x*2);
> > PQexec(append_line);
> > PQexec("end");
>           ^^^
> 
> if this is postgres 4.x, x<2, this won't work at all.
> 
> if this is 4.2, you stand some chance but you don't want to use begin/end.
> (all backend "libpq" calls are executed in the same transaction already.)
> you also don't want to link your function with libpq, *ever*, if it's going
> to be used in the backend -- there are equivalent functions in the backend.
> i don't think you need to do PQsetdb since you're already in a backend
> that is attached to a database.

To my opinion, PQsetdb ist *not* defined in the backend, so you cannot even 
use it.

I tried to do a PQexec without PQsetdb, and it worked as expected.


- Joerg


*********************************************************************
Dipl. Phys. Joerg Plewe               joerg.plewe@mpi-dortmund.mpg.de
MPI fuer molekulare Physiologie
Rheinlanddamm 201
44139 Dortmund
Germany                               +49 (0)231 1206 384
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