Thread

1. USE OF CURSORS IN ECPG

   Maurizio <maurizio@dreamtech-it.com> — 2000-11-07T16:52:00Z

   Hi,
   I'm just starded using ecpg and I have some problem with cursors.
   
   I wrote this lines
   
   exec sql begin declare section;
       char query[500];
       int CodImpianto;
       int Cod1;
       int Cod2;
       char Descr[100];
   exec sql end declare section;
   strcpy(query, "select ............");
   
   exec sql connect db;
   
   sub1()
   {
       exec sql prepare stmtunimpianto from :query;
       exec sql declare CUR_UNIMPIANTO cursor for stmtunimpianto;
       .
       .
       .
   
       exec sql open CUR_UNIMPIANTO using :CodImpianto;
       exec sql fetch CUR_UNIMPIANTO into :CodImpianto, :Descr;
       .
       .
   
       exec sql close CUR_UNIMPIANTO;
       exec sql execute StmtUpdImpianti using :Cod1, :Descr, :Cod2;
       exec sql commit;
   }
   
   I call this routine a lot of time.
   If I rem the commit all works fine but if I execute the commit the cursor was deleted and I receive some errors.
   
   At open cursor : sqlca.sqlcode = -230 Invalid statement namei in line ......
   at fetch           : NOTICE : PerformPortalFetch: portal "cur_unimpianto" not found
   
   Please could anyone help me ?
   
   thanks
   
   regards
   Maurizio Cauci
   DREAMTECH di Cauci Maurizio
   Via Ronchetti, 2 - 21013 Gallarate (VA)
   www.dreamtech-it.com
   

2. Re: USE OF CURSORS IN ECPG

   Michael Meskes <meskes@postgresql.org> — 2000-11-08T11:39:42Z

   On Tue, Nov 07, 2000 at 05:52:00PM +0100, Maurizio wrote:
   > I'm just starded using ecpg and I have some problem with cursors.
   > ...
   >     exec sql prepare stmtunimpianto from :query;
   >     .
   >     .
   >     exec sql commit;
   > ...
   > If I rem the commit all works fine but if I execute the commit the cursor was deleted and I receive some errors.
   > 
   > At open cursor : sqlca.sqlcode = -230 Invalid statement namei in line ......
   > at fetch           : NOTICE : PerformPortalFetch: portal "cur_unimpianto" not found
   
   No surprise here as ending a transaction forces a deallocation of all
   prepared statements. AFAIK that's what the standard says.
   
   Michael
   
   -- 
   Michael Meskes
   Michael@Fam-Meskes.De
   Go SF 49ers! Go Rhein Fire!
   Use Debian GNU/Linux! Use PostgreSQL!
   
   

3. Re: [INTERFACES] USE OF CURSORS IN ECPG

   Maurizio <maurizio.c@libero.it> — 2000-11-09T13:49:29Z

   But, how can I do ?
   I have to recall the same routine many times. I tried to prepare and declare
   the cursor inside the routine but when I compile with ecpg I receive the
   error Cursor already defined.
   
   Maurizio
   
   
   .
   ----- Original Message -----
   From: "Michael Meskes" <meskes@postgresql.org>
   To: "Maurizio" <maurizio@dreamtech-it.com>
   Cc: <pgsql-interfaces@postgresql.org>
   Sent: Wednesday, November 08, 2000 12:39 PM
   Subject: Re: [INTERFACES] USE OF CURSORS IN ECPG
   
   
   > On Tue, Nov 07, 2000 at 05:52:00PM +0100, Maurizio wrote:
   > > I'm just starded using ecpg and I have some problem with cursors.
   > > ...
   > >     exec sql prepare stmtunimpianto from :query;
   > >     .
   > >     .
   > >     exec sql commit;
   > > ...
   > > If I rem the commit all works fine but if I execute the commit the
   cursor was deleted and I receive some errors.
   > >
   > > At open cursor : sqlca.sqlcode = -230 Invalid statement namei in line
   ......
   > > at fetch           : NOTICE : PerformPortalFetch: portal
   "cur_unimpianto" not found
   >
   > No surprise here as ending a transaction forces a deallocation of all
   > prepared statements. AFAIK that's what the standard says.
   >
   > Michael
   >
   > --
   > Michael Meskes
   > Michael@Fam-Meskes.De
   > Go SF 49ers! Go Rhein Fire!
   > Use Debian GNU/Linux! Use PostgreSQL!
   
   
   

4. Re: Re: [INTERFACES] USE OF CURSORS IN ECPG

   Christof Petig <christof.petig@wtal.de> — 2000-11-10T10:52:48Z

   Maurizio wrote:
   
   > But, how can I do ?
   > I have to recall the same routine many times. I tried to prepare and declare
   > the cursor inside the routine but when I compile with ecpg I receive the
   > error Cursor already defined.
   
   you should drop the cursor (exec sql close name;)
   But there is trouble ahead (believe me - see below)
   
   > Maurizioan
   
   ------------
   (Oh, I misunderstood, if you get into trouble with transactions (waiting for
   you ;-() you might consider the following lines)
   ------------
   You certainly should disable autocommit!
     exec sql set autocommit to off;
   otherwise you have no control over when a transaction starts and whether this
   succeded.
   Then at the start of your SubProgram do
     bool my_transaction;
     exec sql begin work;
     my_transaction=!sqlca.sqlcode;
   
   at the end:
     if (my_transaction) exec sql commit work;
   
   This should give you an idea on how to accomplish it. If not feel free to ask
   me.
   
   But (sigh) you need my NOTICE to sqlca patch applied. It's not in 7.0 but in
   7.1! I don't know any other way (I'll attach the patch)
   
   Christof
   
   PS: You might consider applying the patch for (update where not_found) -> 100
   and the cache which doubles ecpg's speed.