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* Cursors for update.., we have to port an informix 9.x appication using cursors for update
@ 2005-12-20 19:46 jmadm <jmadm@montevideo.com.uy>
0 siblings, 2 replies; 4+ messages in thread
From: jmadm @ 2005-12-20 19:46 UTC (permalink / raw)
To: pgsql-interfaces
We have to port an application from Informix 9 CSQL to Postgres 8.1
using Ecpg.
Informix application uses cursors for update to lock all the rows
involved in those cursor. Then an update my occur ussing Current of.
How we can do this with postgres?
Thanks for the reply.
Jorge
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Cursors for update.., we have to port an informix 9.x appication using cursors for update
@ 2005-12-20 21:46 Tom Lane <tgl@sss.pgh.pa.us>
parent: jmadm <jmadm@montevideo.com.uy>
1 sibling, 1 reply; 4+ messages in thread
From: Tom Lane @ 2005-12-20 21:46 UTC (permalink / raw)
To: jmadm@montevideo.com.uy; +Cc: pgsql-interfaces
jmadm <jmadm@montevideo.com.uy> writes:
> We have to port an application from Informix 9 CSQL to Postgres 8.1
> using Ecpg.
> Informix application uses cursors for update to lock all the rows
> involved in those cursor. Then an update my occur ussing Current of.
> How we can do this with postgres?
You can use SELECT FOR UPDATE in the cursor, I think. We don't support
WHERE CURRENT OF, so you'll need an alternative strategy for identifying
the row in the UPDATE command; you could use the table's primary key,
or CTID if you don't mind being quite Postgres-specific.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Cursors for update.., we have to port an informix 9.x appication using cursors for update
@ 2005-12-20 22:11 Jaime Casanova <systemguards@gmail.com>
parent: Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 4+ messages in thread
From: Jaime Casanova @ 2005-12-20 22:11 UTC (permalink / raw)
To: Tom Lane <tgl@sss.pgh.pa.us>; +Cc: jmadm@montevideo.com.uy; pgsql-interfaces
On 12/20/05, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> jmadm <jmadm@montevideo.com.uy> writes:
> > We have to port an application from Informix 9 CSQL to Postgres 8.1
> > using Ecpg.
>
> > Informix application uses cursors for update to lock all the rows
> > involved in those cursor. Then an update my occur ussing Current of.
>
> > How we can do this with postgres?
>
> You can use SELECT FOR UPDATE in the cursor,
in the cursor or instead of the cursor? IIRC, cursors are read only in postgres
--
regards,
Jaime Casanova
(DBA: DataBase Aniquilator ;)
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Cursors for update.., we have to port an informix 9.x appication using cursors for update
@ 2005-12-21 18:23 Michael Meskes <meskes@postgresql.org>
parent: jmadm <jmadm@montevideo.com.uy>
1 sibling, 0 replies; 4+ messages in thread
From: Michael Meskes @ 2005-12-21 18:23 UTC (permalink / raw)
To: pgsql-interfaces; jmadm@montevideo.com.uy
Am Dienstag, 20. Dezember 2005 20:46 schrieb jmadm:
> We have to port an application from Informix 9 CSQL to Postgres 8.1
> using Ecpg.
>
> Informix application uses cursors for update to lock all the rows
> involved in those cursor. Then an update my occur ussing Current of.
>
> How we can do this with postgres?
IIRC there used to be some patches on gborg to implement WHERE CURRENT OF. I
have no idea though whether they work with 8.1.
Michael
--
Michael Meskes
Email: Michael at Fam-Meskes dot De, Michael at Meskes dot (De|Com|Net|Org)
ICQ: 179140304, AIM/Yahoo: michaelmeskes, Jabber: meskes@jabber.org
Go SF 49ers! Go Rhein Fire! Use Debian GNU/Linux! Use PostgreSQL!
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2005-12-20 19:46 Cursors for update.., we have to port an informix 9.x appication using cursors for update jmadm <jmadm@montevideo.com.uy>
2005-12-20 21:46 ` Tom Lane <tgl@sss.pgh.pa.us>
2005-12-20 22:11 ` Jaime Casanova <systemguards@gmail.com>
2005-12-21 18:23 ` Michael Meskes <meskes@postgresql.org>
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