PHP, MySQL, PDO Transactions - Does the code inside try block stop at commit()?

Question

I\'m pretty new to transactions.

Before, what I was doing was something like:

Code Block 1

$db = new PDO(...);

$stmt = $db->prepare(         


        

Answer 1

if you face any error you can do this to rollback all transactions like this

catch(Exception $e){
    $db->rollBack();
    // Failed, maybe write the error to a txt file or something
    return false;
}

Answer 2

The execution is stopped when an exception is thrown.

The first return will not be reached but the catch statement will be executed.

You can even return the commit directly:

$dbh->beginTransaction();
try {
    // insert/update query
    return $dbh->commit();
} catch (PDOException $e) {
     $dbh->rollBack();
     return false;
}

Answer 3

If the transaction fails for whatever reason, the code does stop at the very line where error occurred end then the execution jumps directly to the catch block. So it is sufficient the way you have it written in Code Block 2.

Note that you should always re-throw the Exception after rollback. Otherwise you will never have an idea what was a problem. So it should be

try{
    $stmt = $db->prepare(... 1 ...);
    $stmt->execute();

    $stmt = $db->prepare(... 2 ...);
    $stmt->execute();

    $stmt = $db->prepare(... 3 ...);
    $stmt->execute();

    $db->commit();

    return true;
}catch(Exception $e){
    $db->rollBack();
    throw $e;
}