SQLite 3: two ways to initialize, whats the difference?

Im new to PDO, SQLite3. There is an example:

http://www.tutorialspoint.com/sqlite/sqlite_php.htm

here is another:

http://www.if-not-true-then-false.com/2012/php-pdo-sqlite3-example/

both claims that they use SQLite3 - but one uses new PDO('sqlite:messaging.sqlite3'); while another new SQLite3 which one should I use? Yes, there are differences, because with the 2nd way, the setAttribute() doesnt exists.