Perl error: fetchrow_hashref failed

----- Original Message -----
From: "Jeffrey" <seesej@uswest.net>
To: <pgsql-general@postgresql.org>
Sent: Wednesday, April 12, 2000 10:05 AM
Subject: [GENERAL] Perl error: fetchrow_hashref failed

Hi, I wonder if I might tap the vast knowledge here againg.

I have a perl script that is looping through a statement handle like this.

$statement = "select * from sometable";
$sth=$dbh->prepare($statement);
$sth->execute();

# here is the part I have a question about.
while (%hash_ref = %{$sth->fetchrow_hashref}) {

while (($k,$v) = each (%hash_ref)) {
print ("\n$k == $v"); }
}

I don't think your first loop will work because the %{$b} where $b is undef
will not produce an undef - I think.

See if this works? It ought to be more efficient anyway, because you only
need one hash in my version, not two like your routine (that created by the
fetchrow_hashref call and the hash %hashref itself.

while (defined $hash_ref=$sth->fetchrow_hashref) {
while (($k,$v)=each %$hashref) {
print ("\n$k==$v");
}
}

Your script works fine, but I still get the same error.

I can duplicate this same error with a non-hash ref like this.

$sth=$dbh->prepare("select param1,param2 from sometable");
$sth->execute;

while (($param1,$param2) = $sth->fetchrow_array) {
...... do something with them .
}

My concern is, does the error fetchrow_hashref or _array cause any problems
with the server, postmaster, postgres, etc. I am about to turn a site on
with lots of traffic and I don't want to crash because of these errors.

Thank you
js

All I can say is I get no errors of this kind in my code, which runs

$sth=$dbh->prepare("select param1,param2 from sometable");
$sth->execute;

while (@resultset = $sth->fetchrow_array) {
...... do something with them .
}
$sth->finish;

I don't think calling $sth-finish should make the difference, but maybe if
you have already used $sth once there is a problem?
Try it anyway :->
----------------------------------------------------------------
Moray.McConnachie@computing-services.oxford.ac.uk
----- Original Message -----
From: "Jeffrey" <seesej@uswest.net>
To: "Moray McConnachie" <moray.mcconnachie@computing-services.oxford.ac.uk>;
<pgsql-general@postgresql.org>
Sent: Wednesday, April 12, 2000 12:57 PM
Subject: Re: [GENERAL] Perl error: fetchrow_hashref failed

Your script works fine, but I still get the same error.

I can duplicate this same error with a non-hash ref like this.

$sth=$dbh->prepare("select param1,param2 from sometable");
$sth->execute;

while (($param1,$param2) = $sth->fetchrow_array) {
...... do something with them .
}

My concern is, does the error fetchrow_hashref or _array cause any

problems

with the server, postmaster, postgres, etc. I am about to turn a site on
with lots of traffic and I don't want to crash because of these errors.

Thank you
js

From: "Moray McConnachie"

<moray.mcconnachie@computing-services.oxford.ac.uk>

Date: Wed, 12 Apr 2000 12:45:42 +0100
To: "Jeffrey" <seesej@uswest.net>, " " <pgsql-general@postgresql.org>
Subject: Re: [GENERAL] Perl error: fetchrow_hashref failed

----- Original Message -----
From: "Jeffrey" <seesej@uswest.net>
To: <pgsql-general@postgresql.org>
Sent: Wednesday, April 12, 2000 10:05 AM
Subject: [GENERAL] Perl error: fetchrow_hashref failed

Hi, I wonder if I might tap the vast knowledge here againg.

I have a perl script that is looping through a statement handle like th

is.

$statement = "select * from sometable";
$sth=$dbh->prepare($statement);
$sth->execute();

# here is the part I have a question about.
while (%hash_ref = %{$sth->fetchrow_hashref}) {

while (($k,$v) = each (%hash_ref)) {
print ("\n$k == $v"); }
}

I don't think your first loop will work because the %{$b} where $b is

undef

will not produce an undef - I think.

See if this works? It ought to be more efficient anyway, because you

only

need one hash in my version, not two like your routine (that created by

the

I think the cleanest way to handle this is:

while ($Rhash = $sth->fetchrow_hashref) {
do something with %$Rhash or just refer to $Rhash->{fieldname}
}

The array-based version below, if I remember correctly, can fail in
certain cases, including if both params are undefined. The code above
succeeds because the assignment is always either a hashref or undefined,
never an array partially consisting of undefined values.

BTW, the DBI docs suggest that the *fastest* way to do it is with
$sth->fetchrow_arrayref.

Cheers,
Andy Perrin