How to see query created by Zend DB Adapter

For debugging purposes, how do you print the query Zend_DB makes for you. I did not find it in the docs.
For example if I get an sql error when running this code below. how can I dump the statement it is using to help see what I hosed.

$data = array('FNAME' => 'test name',);
$where = "ID = '14'" ;
$n = $db->update("tablename", $data, $where);