if ($self->{_can_do_transactions}) {
     local $dbh->{AutoCommit} = 0;
     eval {
         code_that_touches_db();
         $dbh->commit;
     };
     if ($@) {
         my $msg = $@;
         eval { $dbh->rollback };
         die $msg;
     }
 }
 else
 {
     code_that_touches_db();
 }

##</code><code>##

 if ($self->{_can_do_transactions}) {

     # If RaiseError is true, begin_work() will:
     #     return true if a new transaction was started
     #     croak if already in a transaction
     #     croak if transactions not supported
     #
     local $dbh->{RaiseError} = 1;
     my $started_a_new_transaction = 0;
     eval { $started_a_new_transaction = $dbh->begin_work };

     eval {
         $code->(@_);
         $dbh->commit if $started_a_new_transaction;
     };
     if ($@)
     {
         my $msg = $@;
         eval { $dbh->rollback } if $started_a_new_transaction;
         die $msg;
     }
 }
 else
 {
     code_that_touches_db();
 }

##</code><code>##

 eval {
     local $dbh->{AutoCommit} = 0;
 };
 $self->{_can_do_transactions} = $@ ? 0 : 1;

##</code><code>##

    # If RaiseError is false, begin_work() will:
    #     return true if a new transaction was started
    #     return false if already in a transaction
    #     croak if transactions not supported
    #
    my $started_a_new_transaction = 0;
    eval {
        local $dbh->{RaiseError} = 0;
        $started_a_new_transaction = $dbh->begin_work;
    };
    $self->{_can_do_transactions} = $@ ? 0 : 1;
    eval { $dbh->rollback } if $started_a_new_transaction;

##</code><code>##

 closing dbh with active statement handles during global destruction

##</code><code>##

 eval {
     my $val = $dbh->{AutoCommit};   # makes error go away?
     local $dbh->{AutoCommit} = 0;
 };
 $self->{_can_do_transactions} = $@ ? 0 : 1;