If you're just plain Lazy, you can do something like this:

my %db;
tie(%db, 'NDBM_File', ...);

my $userdata = \%{$db{userdata}};
my $config   = \%{$db{config}};

if ($userdata->{foo} && $config->{key})
{
     # ...
}
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Using aliases to deep points in your data structure can be a good way to shorten your code. I find that when working "deep", I try and use a pointer as a starting point that is as close as is practical to the final values.