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

##</code><code>##

# use the same args as DBI->connect();
  $self->dbh_config($data_source, $username, $auth, \%attr);

##</code><code>##

$data_source = dbi:DriverName:database=database_name;host=hostname

##</code><code>##

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 }
   );

##</code><code>##

   $dbh = DBI->connect( 
         $data_source,
         config_param('mysql.username'),
         config_param('mysql.password'),
         { RaiseError => 1 }
   );