If you're also using DBIx::Class, this half-pseudo code does the trick. I am running this for real (in three different versions, one is Class::DBI, two are Catalyst) in a couple production situations. Sorry I'm not posting the full working code but that would be a BIG amount of stuff including the DB and everything and I'm not quite ready to share it. I think I included most of the working bits. In has both posts that are threaded (like WordPress "pages," I think) and threaded comments belonging to the post. 

# blog posts (also threaded)
package MyApp::Schema::DB::post;
use base qw/ DBIx::Class /;
__PACKAGE__->load_components qw( PK::Auto Core );
__PACKAGE__->table('post');

# ... missing some regular set-up code

__PACKAGE__->add_columns(qw/ id user parent title body
                             golive created updated
                         /);

__PACKAGE__->belongs_to('parent' => 'MyApp::Schema::DB::post');
__PACKAGE__->has_many('children' => 'MyApp::Schema::DB::post' => 'pare
+nt',
                      { order_by => "golive" }
                      );

# ... missing some other methods
sub parents {
    my ( $self, @parents ) = @_;
    my $parent = $self->parent;
    return @parents unless $parent;
    unshift @parents, $parent;
    die "Unterminating lineage loop suspected!" if @parents > 50;
    $parent->parents(@parents);
}



# comments ... threaded, attached either to a
# parent comment or directly to a post
package MyApp::Schema::DB::comment;
use base qw/ DBIx::Class /;
__PACKAGE__->load_components qw( PK::Auto Core );
__PACKAGE__->table('comment');

__PACKAGE__->add_columns(qw/ id post user parent title body
                           created updated /);

__PACKAGE__->belongs_to('post' => 'Yesh::Schema::DB::post');
__PACKAGE__->belongs_to('parent' => 'MyApp::Schema::DB::comment');
__PACKAGE__->has_many('replies' => 'MyApp::Schema::DB::comment' => 'pa
+rent');

sub depth {
    my $self = shift;
    return 1 + scalar $self->parents;
}

sub parents {
    my ( $self, @parents ) = @_;
    my $parent = $self->parent;
    return @parents unless $parent;
    push @parents, $parent;
    die "Unterminating lineage loop suspected!" if @parents > 100;
    $parent->parents(@parents);
}

[download]
Update: added a necessary "belongs_to."

In reply to Re: message board thread quandary by Your Mother
in thread message board thread quandary by stonecolddevin

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