def close(self):
		'''关闭与数据库的连接'''
		if VERBOSE:
			print 'Database connection CLOSE.'
		self.conn.close()
def execute(self, sql, params=None):
        result = self._no_monkey.execute(self, sql, params)
        if transaction_states[self.db.alias] and is_sql_dirty(sql):
            transaction_states[self.db.alias].mark_dirty()
        return result