local $dbh->{AutoCommit} = 0;
local $dbh->{RaiseError} = 1; 
# You can RaiseError and eval the transaction
# or you can check $sth->err each time and rollback

eval {
      ##Do your read and write here
      $dbh->commit; 
};
if ($@) {
      warn "append failed $@";
      $dbh->rollback;
}