package Dl;
use strict;

use Data::Dumper;
use base 'Class::DBI';
Dl->set_db(Main => "dbi:Pg:dbname=ab", "zby", ***);

package Dl::Usr;
use base 'Dl';
__PACKAGE__->table('usr');
__PACKAGE__->columns(All => 
    qw/uid nick/);
__PACKAGE__->sequence('usr_uid_seq');
__PACKAGE__->has_many(opinions => 'Dl::Opinion');

package Dl::Opinion;
use base 'Dl';
__PACKAGE__->table('opinion');
__PACKAGE__->columns(All => 
    qw/opid uid descr/);
__PACKAGE__->sequence('opinion_opid_seq');
__PACKAGE__->has_a(uid => 'Dl::Usr');

package Main;
my $user = Dl::Usr->create({nick => 'iwiiw'});
$user->delete;

__OUTPUT__
usr is not a column of Dl::Opinion at /usr/local/share/perl/5.8.2/Class/Trigger.pm line 51