Question

哪种方式更好？

BEGIN TRAN
BEGIN TRY
   -- Code here
   COMMIT TRAN
END TRY
BEGIN CATCH
 ROLLBACK TRAN
END CATCH

或

BEGIN TRY
    BEGIN TRAN
    -- Code here

    COMMIT TRAN
END TRY
BEGIN CATCH
 ROLLBACK TRAN
END CATCH

Answer 1

交易不尊重TRY CATCH边界。一旦遇到COMMIT或ROLLBACK，无论事务是在TRY块内部还是在其外部启动，事务都会关闭。

Best practice is to keep your transaction as short as posssible. With this rule, I will prefer 2nd approach.

很棒的文章@ MSDN ...摘要在这里

“..如果TRY块中生成的错误导致当前事务的状态无效，则该事务被归类为不可提交的事务。通常在TRY块之外结束事务的错误会导致事务在TRY块内发生错误时进入不可提交状态。不可提交的事务只能执行读操作或ROLLBACK TRANSACTION。事务不能执行任何会产生写操作或COMMIT TRANSACTION的Transact-SQL语句。 “

In your example 1. There is an issue

BEGIN TRAN
BEGIN TRY
   -- Code here
END TRY
BEGIN CATCH
 ROLLBACK
END CATCH
COMMIT

如果try块内发生异常，则事务将在catch块中回滚。在此步骤之后，COMMIT将触发一个异常，说明没有要提交的开放事务。

Answer 2

BEGIN TRY


   -- Do the obvious checks 1st if something isnt correct raise error and
   -- get out of try block, A transaction will never begin 
      IF (Some Condition 1)
       BEGIN
         RAISERROR('Something gone Wrong',16,1)
       END

      IF (Some Condition 2)
       BEGIN
         RAISERROR('Something gone Wrong',16,1)
       END

--if nothing has gone wrong ... 
-- Now open a transaction 

  BEGIN TRANSACTION

   -- Code here

   COMMIT TRANSACTION   --<-- If nothing goes wrong commit
END TRY

BEGIN CATCH
IF @@TRANCOUNT <> 0
 BEGIN
   ROLLBACK TRANSACTION
 END  


    SELECT ERROR_LINE(),
           ERROR_MESSAGE(),
           ..... Other Error fucntion to collect information
           -- about error

END CATCH

当控件在TRY BLOCK时如果一切顺利，即Sql server不会抛出错误或者你没有引发错误。控制权永远不会进入CATCH BLOCK，因此您必须在TRY Block内进行COMMIT交易。

Try Catch，Begin Commit Rollback的首选表单？

2 个答案: