my $dbh = My::DB->new({server => 'foo', db => 'oops.db'})

##</code><code>##

if ($data->{server} eq 'pg') {
   ...
} elsif ($data->{server} eq 'sqlite') {
   ...
} else {
  Carp::croak "Oops, you tried to access a '$data->{server}' type database, but I have no idea what that is";
}