sub core_drop_meta_for_table {my $self = shift;
  my (%param) = @_;
  my $class = $param{class};
  my $sql = $param{sql};eval "require $class;";            <-----------------------------
  my $driver = $class->dbi_driver;
  my $dbh = $driver->rw_handle;
  my $err;
  eval {
    $dbh->do($sql) or $err = $dbh->errstr;
  };
  # ignore drop errors; the column has probably been
  # removed already
  #if ($err) {
  #    print STDERR "$err: $sqln";
  #}return 0;
}