public function __call_property( $key )
	{
		$result = parent::__call_property( $key );
		
		// when we recive a relation we execute it and save it
		// to the data to avoid mutlitple queries
		if ( $result instanceof Model_Relation )
		{
			return $this->_data_store[$key] = $result->run();
		}
		
		return $result;
	}