Php 迭代PersistentCollection时出现问题

我是一个新的信条，我在一个PersistentCollection上遇到了一个问题，我有一些基本的实体，它们建立了很多关系：

 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;
}

错误日志报告了以下内容，但我无法理解报告的内容

[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

---

问题是我混淆了这些关系，File.rows是OneToMany，而Row.File是manytone。

我在方法中所做的就是$File->getRows（）；foreach（$行作为$行）。。。所以代表我来说没有语法错误。