Table PROJECT
   id (primary key for the table)
   ...

Table ACCOUNT
   id (primary key for the table)
   project_id (reference to PROJECT.id)
   ...

Table QUOTA
   id (primary key for the table)
   account_id (reference to ACCOUNT.id)
   ...

##</code><code>##

Quota->belongs_to(account => 'Account');
Account->belongs_to(project => 'Project');

##</code><code>##

my $project_from_quota = $quota->account()->project();

##</code><code>##

package Quota;
sub project { return shift->account()->project() }
#...
my $project_from_quota = $quota->project();