RE: temporary table "disapears"

You should run this with DBI->trace() turned on to see what DBD::ODBC
actually does. The temp tables should only be dropped when the connection
is closed.

Michael




Extranet
campbelb@xxxxxxxxxxxxxxxxxx - 11.05.2007 00:19


To: martin.evans, dbi-users
cc:
Subject: RE: temporary table "disapears"

Martin, Autocommit off doesn't help local temps persist after the
execute.

Andon said that batching all the commands in the same execute is not an
option for him, so the only working alternative so far is to consider
global temps (##foo). They do persist after an execute and throughout
an entire session.

Consider these examples:

my $s1 = 'create table #foo (a int not null)';
my $s2 = 'insert into #foo values (1)';
my $s3 = 'select * from #foo';
$dbh->{AutoCommit} = 0; # trying to see if this help, but it
doesn't
my $sth;
$sth = $dbh->prepare($s1);
$sth->execute(); # works: table created
$sth = $dbh->prepare($s1);
$sth->execute(); # works: can recreate table because
original is gone
$sth = $dbh->prepare($s2);
$sth->execute(); # doesn't work: table is gone
$sth = $dbh->prepare($s3);
$sth->execute(); # doesn't work: table is gone
$sth = $dbh->prepare("$s1; $s2; $s3");
$sth->execute(); # works: table exists across batched
commands

-----Original Message-----
From: Martin Evans [mailto:martin.evans@xxxxxxxxxxxx]
Sent: Thursday, May 10, 2007 7:39 AM
To: dbi-users@xxxxxxxx
Subject: Re: temporary table "disapears"

CAMPBELL, BRIAN D (BRIAN) wrote:
You're right. It's the the other way around from what I said.
However, when I tested this yesterday it seemed I was getting an error

on the create command also. But I re-examined the results more
carefully today and the create worked OK; it was just the insert that
failed. However they were both run on the same connection (same $dbh
handle). So it seems that local temps don't persist after an
execute() call, as Andon supposed.


What if you turn autocommit off - do the temporary tables exist for
longer then?

Martin
--
Martin J. Evans
Easysoft Limited
http://www.easysoft.com
________________________________

From: michael.peppler@xxxxxxxxxxxxxx
[mailto:michael.peppler@xxxxxxxxxxxxxx]
Sent: Wednesday, May 09, 2007 10:49 PM
To: CAMPBELL, BRIAN D (BRIAN)
Cc: atschauschev@xxxxxxxxx; dbi-users@xxxxxxxx
Subject: RE: temporary table "disapears"



I'm pretty sure that #tmp is a local temporary table, and ##tmp
is a
global temporary table...

So the original problem is most likely that the create table
#tmp and
the insert into #tmp statements aren't being run on the same physical
connection. I don't know DBD::ODBC, but I can tell you that
DBD::Sybase could possibly have opened a second connection under the
covers if it thought the first statement hadn't been completely
processed yet.

Michael





Extranet
campbelb@xxxxxxxxxxxxxxxxxx - 09.05.2007 18:40


To: atschauschev, dbi-users

cc:

Subject: RE: temporary table "disapears"

Actually I tried this against SQL 2000, DBI 1.53 and DBD::ODBC
1.13...

You should be getting 2 errors, the same error from both
prepares.
In
other words, #foo isn't being treated as a proper table name.
Naturally, these statements work fine if you just use foo (which

isn't
temp).

However, #foo should represent a "global temp" table, and this
is not
being accepted as a valid name. Not sure why.

But ##foo works fine, and the table does persist across executes

while
the $dbh connection is open. With 2 #'s, it's a "local temp"
table
which means it's not visible to other sessions. If that's OK,
perhaps
you can use that instead.



-----Original Message-----
From: Andon Tschauschev [mailto:atschauschev@xxxxxxxxx]
Sent: Wednesday, May 09, 2007 8:31 AM
To: dbi-users@xxxxxxxx
Subject: temporary table "disapears"

Hello,

I am using DBI 1.51 and DBD::ODBC 1.13, connecting to MSSQL2005.

Executing following statements:
$sth = $dbh->prepare('create table #foo (a int not null)');
$sth->execute(); $sth = $dbh->prepare('insert into #foo values
(1)');
$sth->execute();

generate an error:
[Microsoft][ODBC SQL Server Driver][SQL Server]Invalid object
name
'#foo'.

So, the temporary table "disapears".... (I tested it on Sybase,
using
DBD::Sybase, too, there is no an error). Since the two
statements are
dynamically created (between come other statements), I cannot
execute
in
one batch $sth = $dbh->prepare('create table #foo (a int not
null)
insert into #foo values (1)); $sth->execute();

at once...

How can I avoid this problem?

Regards!

Andon


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