my $data_source = 'DBI:mysql:'.
         $self->config_param('mysql.database').':'.
         $self->config_param('mysql.host');

   $self->dbh_config( 
         $data_source,
         $self->config_param('mysql.username'),
         $self->config_param('mysql.password'),
         { RaiseError => 1 }
   );