$dbhost = "server";
$dbuser = "test_db";
$dbpass = "test_db";
$dbname = "test";

$mysql_conn_string = "mysql:host=$dbhost;dbname=$dbname";

try{
    $dbConnection = new PDO($mysql_conn_string, $dbuser, $dbpass);
}
catch(PDOException $ex) {

    echo($ex->getMessage());
}

 echo(PDO::errorInfo());

try {
//connect as appropriate as above
$stmt = $dbConnection->prepare('bogus sql');
 } catch(PDOException $ex) {
  echo "An Error occured!"; //user friendly message
  echo($ex->getMessage());
 }