DBI and binding a list of hashes

wfsp has asked for the wisdom of the Perl Monks concerning the following question:

In gmax's excellent DBI recipes under the heading 'Getting a list of hashes' he give this example:

my $sth = $dbh->prepare($query2);
$sth->execute();
my $employees_loh = $sth->fetchall_arrayref({});
[download]

Later, under 'Binding columns and fetching', he explains that:

The fastest method, which you can always count on, is fetchrow_arrayref. It is even faster when you combine it with binding.

Is it useful/possible to bind a list of hashes (as shown above)?.

The following (similar to one of gmax's examples):
update: see note below

$sth->execute($year, $month);
my @array = ();
$sth->bind_col(\(@array));
$sth->fetchall_arrayref({});
[download]

for instance, gives:

DBI bind_col: invalid number of arguments: got handle + 0, expected ha
+ndle + between 2 and 3
Usage: $h->bind_col($column, \$var [, \%attr]) at etc...
[download]

Any pointers?

update: gmax's example is for fetchcol_arrayref

Comment on DBI and binding a list of hashes Select or Download Code

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Re: DBI and binding a list of hashes by Belgarion (Chaplain) on Dec 12, 2005 at 16:53 UTC
I'm not sure I understand what exactly you are asking for. There is pretty good documentation about column binding in the DBI documention. To wit, the documentation for `bind_columns()` shows an example: `$dbh->{RaiseError} = 1; # do this, or check every call for errors $sth = $dbh->prepare(q{ SELECT region, sales FROM sales_by_region }); $sth->execute; my ($region, $sales); # Bind Perl variables to columns: $rv = $sth->bind_columns(\$region, \$sales); # you can also use Perl's \(...) syntax (see perlref docs): # $sth->bind_columns(\($region, $sales)); # Column binding is the most efficient way to fetch data while ($sth->fetch) { print "$region: $sales\n"; }` [download] If you keep reading the documentation for that method, they even show an example of binding to values inside a hash.	[reply] [d/l]

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Re: DBI and binding a list of hashes
by Belgarion (Chaplain) on Dec 12, 2005 at 16:53 UTC

I'm not sure I understand what exactly you are asking for. There is pretty good documentation about column binding in the DBI documention. To wit, the documentation for bind_columns() shows an example:

$dbh->{RaiseError} = 1; # do this, or check every call for errors
$sth = $dbh->prepare(q{ SELECT region, sales FROM sales_by_region });
$sth->execute;
my ($region, $sales);

# Bind Perl variables to columns:
$rv = $sth->bind_columns(\$region, \$sales);

# you can also use Perl's \(...) syntax (see perlref docs):
#     $sth->bind_columns(\($region, $sales));

# Column binding is the most efficient way to fetch data
while ($sth->fetch) {
    print "$region: $sales\n";
}
[download]

If you keep reading the documentation for that method, they even show an example of binding to values inside a hash.

[reply]
[d/l]