final private function getSqlKeyConditions() {
	
		$class		= get_called_class();
		$tableKey	= (array)$class::TABLE_KEY;
		$conds		= array();
		
			foreach ($tableKey as $field) {
				$conds[] = $this->db->escape($field) . ' = ?';
			}
		
		return $conds;

	}