DBD :: CSV-如何获取列名？

#!/usr/bin/env perl
use warnings;
use 5.012;
use DBI;

my $options  = { RaiseError => 1, PrintError => 0, f_ext => \".csv/r\" };
my $dbh = DBI->connect( \"dbi:CSV:\", undef, undef, $options ) or die $DBI::errstr;

my $table = \'test\';
$dbh->do( \"CREATE TEMP TABLE $table ( id INT, size INT )\" );
my $sth = $dbh->prepare( \"INSERT INTO $table ( id, size ) VALUES( ?, ? )\" );
$sth->execute( 1, 235 );
$sth->execute( 2, 42 );

use Data::Dumper;
say Dumper $dbh->{csv_tables}{$table}{col_names};

$dbh->{csv_tables}{$table} = { skip_first_row => 0 };
$sth = $dbh->prepare( \"SELECT * FROM $table\" );
$sth->execute;
my @first_row = $sth->fetchrow_array;
say \"@first_row\\n\";

$sth = $dbh->column_info( \'\', \'\', $table, \'\' );
my $ref = $sth->fetchall_arrayref;
say \"@$_\" for @$ref;


# $VAR1 = undef;
#
# 1 235
#
# Can\'t call method \"fetchall_arrayref\" on an undefined value at ./so.pl line 25.