Greetings Monks, I'm using Class::DBI with two classes, A and B with A having many Bs. The database is set up like so:

mysql> select * from test_a;
+-----+
| oid |
+-----+
|   1 |
+-----+

mysql> select * from test_b;
+-----+------+------+
| oid | aoid | flag |
+-----+------+------+
|   1 |    1 |    0 |
|   2 |    1 |    0 |
|   3 |    1 |    1 |
+-----+------+------+
3 rows in set (0.01 sec)

Where aoid references and oid in test_a .

Below is the code for the two classes

Testing2.pm

use strict;
use warnings ;
package Testing2;
use base 'Testing';

Testing2->table('test_a');
Testing2->columns(Primary => qw/oid/ ) ;

Testing2->has_many( bs => 'Testing3', 'aoid');



sub flagged {
    my $self  =shift ;
    my @bs = $self->bs( flag => 1 ) ;
    return shift @bs ;
}

sub flagged2 {
    my $self  =shift ;

    unless(defined($self->{f})) {
        my @bs = $self->bs( flag => 1 ) ;
        $self->{f} = shift @bs ;
    }
    return $self->{f} ;

}

sub DESTROY {
    my $self = shift;
    print "Destroying a " . $self->oid . "\n";
}

1;
[download]

Testing3.pm

use strict;
use warnings ;

package Testing3;
use base 'Testing';

Testing3->table('test_b');
Testing3->columns(Primary => qw/oid/ ) ;
Testing3->columns(Essential => qw/aoid flag/ ) ;
Testing3->has_a( aoid => 'Testing2');

sub DESTROY {
    my $self = shift;
    print STDERR "Destroying b " . $self->oid . "\n";
}

1;
[download]

Now I need to be able to find the particular B that corrosponds to a particular A where flag is 1. So in class A I have:

sub flagged {
    my $self  =shift ;
    my @bs = $self->bs( flag => 1 ) ;
    return shift @bs ;
}
[download]

But in my code, flagged is called many times per execution and I'd really like to be able to cache the results of the search so it's only performed once. I tried the following:

sub flagged2 {
    my $self  =shift ;
    unless(defined($self->{f})) {
        my @bs = $self->bs( flag => 1 ) ;
        $self->{f} = shift @bs ;
    }
    return $self->{f} ;
}
[download]

The problem is now that the objects a and b no longer get destroyed when the execution finishes because the reference count never hits 0. This is causing problems under mod_perl.

Is there a way to ensure the objects get destroyed or alternatively a better way to do this ?

Cheers, Simon N

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