Работа с базами через DBI

my $dbh = DBI->connect($dsn,$user,$pass,{RaiseError=>1,PrintError=>0,AutoCommit=>1});

my $sth=$dbh->prepare('SELECT * FROM users WHERE id=?');
$sth->execute($id);

$dbh->{AutoCommit} = 0;
eval { debit(); credit(); $dbh->commit; 1 };
if ($@) { my $err = $@; eval { $dbh->rollback }; die $err }

my $rows = $sth->execute(@bind);
while (my $row = $sth->fetchrow_hashref) {
    handle_row($row);
}

my $dbh=DBI->connect('dbi:SQLite:dbname=:memory:','','',{RaiseError=>1});

my $dbh = DBI->connect($dsn,$user,$pass);
$dbh->do('UPDATE t SET x=1');

my $sql = "SELECT * FROM users ORDER BY $column";

debit();
credit();

while (my $row = $sth->fetchrow_hashref) {
    handle_row($row);
}

my $dbh = DBI->connect(
    $ENV{PROD_DSN}, $user, $password,
    { RaiseError => 1, AutoCommit => 1 },
);

my $dbh = DBI->connect($dsn,$user,$pass,{RaiseError=>1,PrintError=>0}) or die DBI->errstr;

my %allowed=(name=>'name',created=>'created_at');
my $col=$allowed{$column}//die 'bad';
my $sth=$dbh->prepare("SELECT * FROM users ORDER BY $col");

eval { $dbh->begin_work; debit(); credit(); $dbh->commit; 1 } or do { my $e=$@; eval{$dbh->rollback}; die $e };

while (my $row = $sth->fetchrow_hashref) {
    handle_row($row);
}
die $sth->errstr if $sth->err;

my $dsn=$ENV{TEST_DSN}//'dbi:SQLite:dbname=:memory:';
die 'production refused' if looks_production($dsn);