Here's an example of using transactions in PDO.

NOTE: Calling beginTransaction() turns off auto commit automatically.

<?php
try {
  $db->beginTransaction();
 
  $db->exec("SOME QUERY");
 
  $stmt = $db->prepare("SOME OTHER QUERY?");
  $stmt->execute(array($value));
 
  $stmt = $db->prepare("YET ANOTHER QUERY??");
  $stmt->execute(array($value2, $value3));
 
  $db->commit();
} catch(PDOException $ex) {
  // Something went wrong rollback!
  $db->rollBack();
  echo $ex->getMessage();
}