When Extending Zend_Db_Table_Abstract to Create a Join it Crashes MySQL

I want to understand why this works perfect with out a problem.

$this->db   =   Zend_Db_Table_Abstract::getDefaultAdapter();

   public function getMessages()
    {

        $select = $this->db->select();
        $select
            ->from('Mail_Text', '*')
            ->join(
                array('Mail' => 'Mail'),
                'Mail.id = Mail_Text.parent_id', '*'
                );
        return $this->db->fetchAll($select)开发者_开发百科;
          }

Now if I do this by extending Zend_Db_Table_Abstract

class Mail_Model_Text extends Zend_Db_Table_Abstract
{

        protected $_name = 'Mail_Text';
        public function fetchMessges(){
        $select = $this->select();
        $select->setIntegrityCheck(false)
            ->from($this->_name, '*')
            ->join(
                array('Mail' => 'Mail'),
                'Mail.id = Mail_Text.parent_id', '*'
                );
        return $this->fetchAll($select);

}
}

This crashes MySql I wanted to keep the code separate but I can join theses tables. All the Single select and updates query's work perfect. I have research all over the net and can't seem to find the solution to this puzzle. Any Help to his would be great Thanks in advance.

---

You don't need the from() statement or need to alias the table to the same name:

class Mail_Model_Text extends Zend_Db_Table_Abstract { protected $_name = 'Mail_Text';

public function fetchMessges()
{
    $select = $this->select();
    $select->setIntegrityCheck(false)
        ->join('Mail', 'Mail.id = Mail_Text.parent_id');

    return $this->fetchAll($select);
}

}

Also, ensure that you have correctly indexed your tables.