/**
  * Performs a DELETE on the database, given a Newsletter or Criteria object OR a primary key value.
  *
  * @param      mixed $values Criteria or Newsletter object or primary key or array of primary keys
  *              which is used to create the DELETE statement
  * @param      PropelPDO $con the connection to use
  * @return int The number of affected rows (if supported by underlying database driver).  This includes CASCADE-related rows
  *				if supported by native driver or if emulated using Propel.
  * @throws PropelException Any exceptions caught during processing will be
  *		 rethrown wrapped into a PropelException.
  */
 private static function doDeleteBeforeReferencing($values, PropelPDO $con = null)
 {
     if ($con === null) {
         $con = Propel::getConnection(NewsletterPeer::DATABASE_NAME, Propel::CONNECTION_WRITE);
     }
     if ($values instanceof Criteria) {
         // rename for clarity
         $criteria = clone $values;
     } elseif ($values instanceof Newsletter) {
         // it's a model object
         // create criteria based on pk values
         $criteria = $values->buildPkeyCriteria();
     } else {
         // it's a primary key, or an array of pks
         $criteria = new Criteria(NewsletterPeer::DATABASE_NAME);
         $criteria->add(NewsletterPeer::ID, (array) $values, Criteria::IN);
     }
     // Set the correct dbName
     $criteria->setDbName(NewsletterPeer::DATABASE_NAME);
     $affectedRows = 0;
     // initialize var to track total num of affected rows
     try {
         // use transaction because $criteria could contain info
         // for more than one table or we could emulating ON DELETE CASCADE, etc.
         $con->beginTransaction();
         // cloning the Criteria in case it's modified by doSelect() or doSelectStmt()
         $c = clone $criteria;
         $affectedRows += NewsletterPeer::doOnDeleteCascade($c, $con);
         // Because this db requires some delete cascade/set null emulation, we have to
         // clear the cached instance *after* the emulation has happened (since
         // instances get re-added by the select statement contained therein).
         if ($values instanceof Criteria) {
             NewsletterPeer::clearInstancePool();
         } elseif ($values instanceof Newsletter) {
             // it's a model object
             NewsletterPeer::removeInstanceFromPool($values);
         } else {
             // it's a primary key, or an array of pks
             foreach ((array) $values as $singleval) {
                 NewsletterPeer::removeInstanceFromPool($singleval);
             }
         }
         $affectedRows += BasePeer::doDelete($criteria, $con);
         NewsletterPeer::clearRelatedInstancePool();
         $con->commit();
         return $affectedRows;
     } catch (Exception $e) {
         $con->rollBack();
         throw $e;
     }
 }