Quoted from the above official PHP docs: "If your application does not catch the exception thrown from the PDO constructor, the default action taken by the zend

Quoted from the above official PHP docs: "If your application does not catch the exception thrown from the PDO constructor, the default action taken by the zend engine is to terminate the script and display a back trace. This back trace will likely reveal the full database connection details, including the username and password. [...]"