I have InnoDB tables that we access via a PDO API from PHP. Now, I've read that for INSERT and UPDATE statements, it would probably be a good idea to use InnoDB transactions. Since auto commit is set to 1, it would commit the query as soon as it is made. So if I group a bunch of INSERTs together and do:

```
$GLOBALS['dbh']->query('BEGIN');
[multiple INSERT queries here]
$GLOBALS['dbh']->query('COMMIT');

```

It's supposed to be more efficient. 

Questions:

1. Is this correct?
2. I also read that certain APIs make use of their own transactions and was wondering if anyone knew if PDO does this. In other words, should I worry about doing this at all or let PDO handle transactions?
3. In the case that PDO does handle transactions, am I screwing everything up with the above queries?

Thanks.