At which level do you want to find out? DBIx::Class::Schema::Versioned uses this construct:

sub _source_exists
{
    my ($self, $rs) = @_;

    my $c = eval {
        $rs->search({ 1, 0 })->count;
    };
    return 0 if $@ || !defined $c;

    return 1;
}
[download]

This is called on a $schema object, and passed a plain $resultset object.

Or you could just use Versioned.

C.