Because no examples are provided, and to alleviate any confusion as a result, the setAttribute() method is invoked like so:
setAttribute(ATTRIBUTE, OPTION);
So, if I wanted to ensure that the column names returned from a query were returned in the case the database driver returned them (rather than having them returned in all upper case [as is the default on some of the PDO extensions]), I would do the following:
<?php
$dbConnection = new PDO($dsn, $user, $pass);
$dbConnection->setAttribute(PDO::ATTR_CASE, PDO::CASE_NATURAL);
?>
Hope this helps some of you who learn by example (as is the case with me).
.Colin