如何才能保障存储过程嵌套调用的原子性

这段代码用于解决存储过程之间嵌套调用的全局原子性问题:

declare @ TranStarted bit
SET @ TranStarted = 0
if(@ @ trancount = 0)-用于嵌套
begin
begin transaction
SET @ TranStarted = 1
END
ELSE
SET @ TranStarted = 0
.....
IF(@ TranStarted = 1)
BEGIN
SET @ TranStarted = 0
提交事务
END