The Class::DBI docs aren't especially clear on this but might_have relationships have to have identical primary keys in both tables. This makes a has_a relationship your only option since the Author table naturally doesn't have a primary key of articleId.

If you'd like to have the functionality you're describing, you could do something like the following (quite untested):

package MPDatabase::Article;
# ... set up table ...

__PACKAGE__->has_a(authorId => 'MPDatabase::Author');
{
    no strict 'refs';
    foreach my $m(MPDatabase::Author->columns()){

        # keep from overriding existing methods...
        next if __PACKAGE__->can($m);

        # deploy shortcut sub
        *{$m} = sub {
            my $obj = shift;
            return $obj->authorId->$m(@_);
        };
    }
}
[download]

Incidentally, I've found might_have relationships to be of rather limited use.

-- Brian

UPDATE: tweaked method detection