Thread: Trying to execute several queries involving temp tables in a PHP script

Hello fello PostgreSQL users,

with PHP 5.3.3 and PostgreSQL 8.4.11
(and a pgbouncer, but I've tried without it too)
I'm trying to execute several SQL queries
with 2 temp tables (listed below) and then use
the result of a final join to construct a JSON array.

Unfortunately my script using prepare/execute
(and I've tried query() too) fails with PHP error:
"cannot insert multiple commands into a prepared statement".

And when I split my statements into multiple
prepare()/execute() or query() calls,
then the temp. tables aren't found anymore.

Any ideas please on how to handle this situation
in PHP scripts, do I really have to encapsulate
my calls into a pl/PgSQL function?

More details on my query and setup:
http://stackoverflow.com/questions/11010784/error-cannot-insert-multiple-commands-into-a-prepared-statement

And below is my PHP code:

try {
        $options = array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION);
        $db = new PDO(sprintf('pgsql:host=%s port=%u; dbname=%s',
                DBHOST, DBPORT, DBNAME), DBUSER, DBPASS, $options);

        $sth = $db->prepare("
            start transaction;
            create temporary table temp_ids (id varchar not null) on
commit drop;
            insert into temp_ids (id)
                    select id
                    from pref_money
                    where yw = to_char(current_timestamp - interval '1
week', 'IYYY-IW')
                    order by money
                    desc limit 10;

            create temporary table temp_rids (rid integer not null) on
commit drop;
            insert into temp_rids (rid)
                    select rid
                    from pref_cards
                    where stamp > now() - interval '1 day' and
                    id in (select id from temp_ids) and
                    bid = 'Misere' and
                    trix > 0;

            SELECT r.rid, r.cards, to_char(r.stamp, 'DD.MM.YYYY
HH24:MI') as day,
                    c.bid, c.trix, c.pos, c.money, c.last_ip, c.quit,
                    u.id, u.first_name, u.avatar, u.female, u.city,
u.vip > CURRENT_DATE as vip
                    FROM pref_rounds r, pref_cards c, pref_users u
                    WHERE u.id = c.id and
                        r.rid = c.rid and
                        r.rid in (select rid from temp_rids)
                    order by rid, pos;
            commit;
        ");
        $sth->execute();
        while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
              # construct a JSON array of objects
        }
} catch (Exception $e) {
        exit('Database problem: ' . $e->getMessage());
}

Thank you
Alex

On 13 June 2012 15:12, Alexander Farber <alexander.farber@gmail.com> wrote:
> And when I split my statements into multiple
> prepare()/execute() or query() calls,
> then the temp. tables aren't found anymore.

Did you remember to wrap them in a transaction like you did in your
prepared statement?

--
If you can't see the forest for the trees,
Cut the trees and you'll see there is no forest.

Hi Alexander,

 Onsdag 13. juni 2012 15.12.33 skrev Alexander Farber :

> Any ideas please on how to handle this situation
> in PHP scripts, do I really have to encapsulate
> my calls into a pl/PgSQL function?

I believe that Misa Simic's idea that you can do it all in a single query
without temp tables is correct. But anyway, it's always a good idea to
encapsulate multiple interdependent queries in a single pl/pgsql function. I
tend to keep my PHP code as simple as possible, and do most of the work inside
the database.

regards, Leif
http://code.google.com/p/yggdrasil-genealogy/

I agree with approach to have all in functions... In that case there would not be a problem with temp tables because of inside 1 transaction they would work...

Thank you Misa, the without-temp-tables query has worked flawlessly.


On Wed, Jun 13, 2012 at 5:01 PM, Misa Simic <misa.simic@gmail.com> wrote:
> I think you can have all in one query, without temp tables:
>
>  SELECT r.rid, r.cards, to_char(r.stamp, 'DD.MM.YYYY
> HH24:MI') as day,
>                    c.bid, c.trix, c.pos, c.money, c.last_ip, c.quit,
>                    u.id, u.first_name, u.avatar, u.female, u.city,
> u.vip > CURRENT_DATE as vip
>                    FROM pref_rounds r, pref_cards c, pref_users u
>                    WHERE u.id = c.id and
>                        r.rid = c.rid and
>                        r.rid in (
>
>  select rid
>                    from pref_cards
>                    where stamp > now() - interval '1 day' and
>                    id in (
>  select id
>                    from pref_money
>                    where yw = to_char(current_timestamp - interval '1
> week', 'IYYY-IW')
>                    order by money
>                    desc limit 10
>
> ) and
>                    bid = 'Misere' and
>                    trix > 0
>
>
> )
>                    order by rid, pos;