Examples from the docs:

my $session = new CGI::Session(
          "driver:MySQL", undef, {Directory=>"/tmp"}
      );

##</code><code>##

my $session = new CGI::Session(
          "driver:MySQL", undef, {Handle=>"$dbh"}
      );

/Examples

##</code><code>##

my $session = new CGI::Session(
          "driver:MySQL", undef, {Class::DBI=>"TableObject"}
      );