use DBI;

$dbName= 'testdb';
$dbHost = 'localhost';
$dbUser = 'testuser';
$dbPass = 'testpasswort';

$dsn="dbi:PgPP:dbname=$dbName;host=$dbHost;port=5432";
$dbh=DBI->connect("$dsn","$dbUser","$dbPass") or die "Datenbank nicht erreichbar";

$a='?';
$b="b";

$sql="INSERT INTO test (text1,text2) VALUES (?,?)";
$prep_sql=$dbh->prepare($sql) or die p$dbh->errstr;
$prep_sql->execute($a,$b) or $dbh->errstr;
$prep_sql->finish;