迭代PersistentCollection的问题

我是Doctrine的新手，我在PersistentCollection上迭代时遇到了一个问题，我有一些基本的实体设置了多对多关系:

 class File {
     /**
      * @ManyToMany(targetEntity="Row", mappedBy="file")
      **/
     protected $rows;
     public function __construct()
     {
         $this->rows = new ArrayCollection();
     }
     public function getRows()
     {
         return $this->rows; //this seems to return a persistantCollection
     } 
}
class Row {
    /**
     * @ManyToOne(targetEntity="File", inversedBy="rows")
     **/
    protected $file;
}

错误日志报告以下内容，但我不明白报告的是什么。

[02-May-2013 09:07:29 UTC] PHP Notice:  Undefined index: id in /Applications/MAMP/htdocs/NiCE/datatable.php on line 9
[02-May-2013 09:07:29 UTC] PHP Notice:  Undefined index: joinTable in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Mapping/DefaultQuoteStrategy.php on line 90
[02-May-2013 09:07:29 UTC] PHP Notice:  Undefined index: joinTable in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php on line 969
[02-May-2013 09:07:29 UTC] PHP Warning:  Invalid argument supplied for foreach() in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php on line 969
[02-May-2013 09:07:29 UTC] PHP Notice:  Undefined index: joinTable in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Mapping/DefaultQuoteStrategy.php on line 90
[02-May-2013 09:07:29 UTC] PHP Notice:  Undefined index: joinTable in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php on line 1249
[02-May-2013 09:07:29 UTC] PHP Warning:  Invalid argument supplied for foreach() in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php on line 1251
[02-May-2013 09:07:29 UTC] PHP Fatal error:  Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'ON' at line 1' in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/dbal/lib/Doctrine/DBAL/Connection.php:646
Stack trace:
#0 /Applications/MAMP/htdocs/NiCE/vendor/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(646): PDO->query('SELECT t0.id AS...')
#1 /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php(997): Doctrine'DBAL'Connection->executeQuery('SELECT t0.id AS...', Array, Array)
#2 /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/BasicEntityPersister.php(928): Doctrine'ORM'Persisters'BasicEntityPersister->getManyToManyStatement(Array, Object(File))
#3 /Applications/MAMP/htdocs/NiCE/vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php(2694): Doctrine'ORM'Persisters'BasicEntityPersister->loadMany in /Applications/MAMP/htdocs/NiCE/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php on line 47