Class::DBI struggles

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

Esteemed Monks,

I am using Class::DBI in a webapp. I have a table "block" which can have up to 14 children in a table "adslot" Here is the relevant portion of my Class::DBI module:

package admt::cdbi::adslot;
use base 'cdbi';

__PACKAGE__->set_up_table('adslot');
__PACKAGE__->has_a('blockid' => 'admt::cdbi::block');

package admt::cdbi::block;

use base 'cdbi';

__PACKAGE__->set_up_table('block');
__PACKAGE__->has_many('adslot' => ['admt::cdbi::adslot', 'blockid']);
[download]

And here is the relevant SQL for the table structures:

CREATE TABLE `adslot` (
  `id` bigint(20) unsigned NOT NULL auto_increment,
  `blockid` bigint(20) NOT NULL default '0',
  `sl_position` int(11) NOT NULL default '0',
  `sl_keywords_EN` varchar(255) NOT NULL default '',
  `sl_keywords_FR` varchar(255) NOT NULL default '',
  `sl_start` datetime NOT NULL default '0000-00-00 00:00:00',
  `sl_end` datetime NOT NULL default '0000-00-00 00:00:00',
  `sl_section` varchar(255) NOT NULL default '',
  `sl_smallimage_EN` varchar(255) NOT NULL default '',
  `sl_smallimage_FR` varchar(255) NOT NULL default '',
  `sl_smallimagealt_EN` varchar(255) NOT NULL default '',
  `sl_smallimagealt_FR` varchar(255) NOT NULL default '',
  `sl_smallimagelink_EN` varchar(255) NOT NULL default '',
  `sl_smallimagelink_FR` varchar(255) NOT NULL default '',
  `sl_shortdesc_EN` varchar(255) NOT NULL default '',
  `sl_shortdesc_FR` varchar(255) NOT NULL default '',
  `sl_shortdesclink_EN` varchar(255) NOT NULL default '',
  `sl_shortdesclink_FR` varchar(255) NOT NULL default '',
  `sl_depcity` text NOT NULL,
  `sl_deal` varchar(255) NOT NULL default '',
  `sl_iframe` varchar(255) NOT NULL default '',
  PRIMARY KEY  (`id`)
) TYPE=MyISAM;

CREATE TABLE `block` (
  `id` bigint(20) unsigned NOT NULL auto_increment,
  `blk_key` varchar(32) NOT NULL default '',
  `blk_start` datetime NOT NULL default '0000-00-00 00:00:00',
  `blk_end` datetime NOT NULL default '0000-00-00 00:00:00',
  `blk_desc` varchar(80) NOT NULL default '',
  `blk_notes` varchar(255) NOT NULL default '',
  `blk_app` varchar(32) NOT NULL default '',
  `blk_app_date` date NOT NULL default '0000-00-00',
  `blk_app_by` varchar(32) NOT NULL default '',
  PRIMARY KEY  (`id`)
) TYPE=MyISAM;
[download]

Now, in my code, given that I have the 'od' in "block" I want to get the associated "adslot"'s. So I do this:

  my $block = admt::cdbi::block->retrieve( 'id' => $q->param('blockid'
+) );
  my $slots = $block->adslot;
  my $otext;
  while ( my $slotdata = $slots->next ) {
    $otext .= Dumper $slotdata, "\n";
  }
[download]

As expected, $slots is a Class::DBI::Iterator and looks like this:

$VAR1 = bless( {
                 '_data' => [
                              {
                                'id' => '1'
                              },
                              {
                                'id' => '2'
                              }
                            ],
                 '_place' => 3,
                 '_mapper' => [
                                'blockid'
                              ],
                 '_class' => 'admt::cdbi::adslot'
               }, 'Class::DBI::Iterator' );
[download]

But when I iterate over it, $otext produces the following:

$VAR1 = bless( {
                 'id' => '1'
               }, 'admt::cdbi::block' );
$VAR1 = bless( {
                 'id' => '1'
               }, 'admt::cdbi::block' );
;
[download]

Which tells me that the iterator is returning objects of the parent class, not the child class!

Can abybody help please? Where have I gone wrong?

jdtoronto

Comment on Class::DBI struggles Select or Download Code

Replies are listed 'Best First'.
Re: Class::DBI struggles by rhesa (Vicar) on Apr 26, 2006 at 18:30 UTC
That's because you're mapping the has_many items to call the block_id accessor of the related objects. In other words, you're getting yourself back. Change `__PACKAGE__->has_many('adslot' => ['admt::cdbi::adslot', 'blockid']);` [download] to `__PACKAGE__->has_many('adslot' => 'admt::cdbi::adslot');` [download] and try again :) See http://search.cpan.org/~tmtm/Class-DBI-v3.0.14/lib/Class/DBI.pm#Mapping for the details.	[reply] [d/l] [select]
Re^2: Class::DBI struggles by jdtoronto (Prior) on Apr 26, 2006 at 19:06 UTC
Thank you rhesa, after I posted I wondered if that is what I was doing. jdtoronto	[reply]