How to do a DBIx subquery?

[nysus]

I'm not sure if "subquery" is the appropriate term in my question. I'm new to DBIx. I'm using the WordPress::DBIC::Schema module.

I have the following module:

use Moose;
use WordPress::DBIC::Schema;
use namespace::autoclean;

has 'schema'  => (is => 'ro',
                  isa => 'WordPress::DBIC::Schema',
                  lazy => 1,
                  builder => '_set_schema');

has 'rs'      => (is => 'ro',
                  isa => 'DBIx::Class::ResultSet',
                  lazy => 1,
                  builder => '_set_resultset');

has 'results' => (is => 'ro',
                  isa => 'WordPress::DBIC::Schema::ResultSet::WpPost',
                  lazy => 1,
                  builder => '_set_results');

sub _set_schema {
  my $s = shift;
  my $db = $s->subdomain;
  my $user = $s->_db_user;
  my $pass = $s->_db_pass;
  my $schema = WordPress::DBIC::Schema->connect("dbi:mysql:database=$d
+b", $user, $pass);
  return $schema;
}

sub _set_resultset {
  my $s = shift;
  return $s->schema->resultset('WpPost');
}

sub _set_results {
  my $s = shift;
  return $s->rs->search({ post_type => 'nav_menu_item' },
                        { order_by => { -asc => 'id' } });
}


sub dump_meta {
  my $s = shift;

  my %ids;

  while ( my $thing = $s->results->next ) {
    logd $thing->post_title;
    my $id = $thing->id;
    foreach my $meta ($thing->metas) {
      $ids{$id}{$meta->meta_key} = $meta->meta_value;
    }
  }
  $s->results->reset;

  logd \%ids;
}

sub get_title {
  my $s = shift;
  my $id = shift;

  my $results = $s->results->find($id);
  my $title = $results->post_title;

  if ($title) {
    return $title;
    $s->results->reset;
  }

  ############# Trying to figure out this part, does not work ########
+############ 
  my $post_id = $results->metas->select('_menu_item_object_id');
  print  $post_id . "\n";

}

So the dump_meta function works fine. You can see there how the meta values associated with a post are printed out. I want to try to access a single meta_value for an associated meta_key in the get_title method. I could loop through all the values like I did in dump_meta and pull it out that way but I'm wondering if there is a better way. Thanks!

[nysus]

After a lot of trial and error, I stumbled on a solution:

my $post_id = $results->metas->find( {meta_key => '_menu_item_object_i
+d'} )->meta_value;

[nysus]

I think I need to do a prefetch as illustrated here

I tried:

  my $results = $s->results->find($id, {
      prefetch => ['metas']
    } );
  my $post_id = $results->_menu_item_object_id;

I just got an error, though: Can't locate object method "_menu_item_object_id" via package "WordPress::DBIC::Schema::Result::WpPost"