Question

I’m using PDO with a try…catch statement. I want to confirm with you guys if I understand this correctly. Do I put $dbhandler = NULL before the throw

$dbhandler = NULL;
if(!$sthandler->rowCount()) throw new invalidUplineException();

or after the throw

if(!$sthandler->rowCount()) throw new invalidUplineException();
$dbhandler = NULL;

Answer 1

When a exception is thrown, the script execution jumps to the next matching catch() block (if you are inside a try{} block) or stops completely (if the exception is not caught). This behaviour is not related to PDO, it’s how exceptions work in all languages that support them. Thus the $dbhandler = NULL; part in your second example will never be executed. Here’s a simple test you can run:

<?php

try{
    throw new Exception('This exception will be caught');
    echo 'Exception thrown, this line will not run' . PHP_EOL;
}catch(Exception $e){
    echo 'Exception was caught as expected' . PHP_EOL;
}

throw new Exception('This exception will not be caught. Script ends here.');
echo 'Exception thrown, this line will not run either.' . PHP_EOL;