title: Is it necessary to write ROLLBACK if queries fail?
body: <p>I write <p>
  <code>mysql_query("SET AUTOCOMMIT=0");</code><br>
  <code>mysql_query("START TRANSACTION");</code> <p>
  before I write all queries. Then check if all of them are true and then write: <p>
  <code>mysql_query("COMMIT");</code> <p>
  But if one of query fails, I just pass COMMIT query. So do I really need ROLLBACK function if one of the queries fail? Because without ROLLBACK it also works.<br>
  Thanks.</p>