Howard J. Rogers wrote:
> Richard Foote wrote:
>
>> "Howard J. Rogers" <hjr_at_dizwell.com> wrote in message
>> news:419c730a$0$25115$afc38c87_at_news.optusnet.com.au...
>>
>>> DA Morgan wrote:
>>>
>>>> Howard J. Rogers wrote:
>>>>
>>>>
>>>>> Rahul Jain wrote:
>>>>>
>>>>>
>>>>>> Why is DDL required to be the last statement in a transaction?
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Because there is an implicit commit before and after each and every
>>>>> DDL statement.
>>>>>
>>>>> Regards
>>>>> HJR
>>>>
>>>>
>>>>
>>>> You are absolutely correct Howard ... but I fail to see what your
>>>> answer
>>>> has to do with the question. But then its late and I'm tired.
>>>
>>>
>>>
>>> Well, I'm no developer, but I was always taught that a transaction
>>> starts with some piece of DML and ends when you say 'commit' (or
>>> rollback, of course).
>>>
>>> Insert money into new bank account;
>>> Delete money from old account;
>>> Commit both changes;
>>>
>>> If DDL implies a commit, surely that therefore must count as the
>>> termination of a transaction? And therefore by definition, the DDL
>>> statement becomes the last statement in a transaction.
>>>
>>> Insert money into new bank account;
>>> Delete money from old account;
>>> Drop table EMP;
>>>
>>> ...which achieves exactly the same thing as before.
>>>
>>> Since both you and Richard appear to agree that a piece of DDL is not
>>> necessarily the last statement in a transaction, I guess I must be
>>> missing something. Enlightenment from either would therefore be
>>> appreciated.
>>>
>>
>>
>> Hi Howard,
>>
>> Oh how the English language can confuse and deceive !!
>>
>> "A piece of DDL is not necessarily the last statement in a
>> transaction" because the last statement in a transaction is generally
>> a commit or a rollback !!
>>
>> Just like you said !!
>>
>> The way *I* read the question "Why is DDL required to be the last
>> statement in a transaction?" is that DDL is *required* to be the last
>> statement in a transaction. I'm simply of the opinion that *no* DDL is
>> required to be the last statement in a transaction, and that a piece
>> of DDL is not necessarily the last statement in a transaction because
>> a commit or a rollback *is* generally the last statement of a
>> transaction.
>>
>> Now read my earlier response and hopefully it makes sense.
>>
>> Sometimes the bleedin obvious isn't so bleedin obvious ...
>>
>> Cheers
>>
>> Richard
>
>
> I still don't get the subtlety you see.
>
> All DDL issues a commit. Therefore, taking the word "required" out of
> the equation, all DDL statements WILL be the last statement in a
> transaction, whether you like it or not.
>
> Cut and dice it any way you care to, but the second you issue a DDL
> statement, you've just terminated your transaction.
>
> Is the perceived ambiguity here in the use of the word "required"
> perhaps? On the grounds that it seems to imply someone or some document
> demanding that it should be?? I'd say that was irrelevant. It's not that
> there is some law in the Universe stating "thou shalt issue DDL last".
> It's that there's a law which states "DDL finishes transactions, so the
> DDL will logically and inevitably be the last statement in a transaction".
>
> We are not dealing with subjunctives here, in other words ("should"). We
> are dealing with imperatives ("will").
>
> As the line in a Benjamin Britten opera has it: "It seems we agree but
> are not of the same opinion"!!
>
> Regards
> HJR
It is the word "required" that got me ... that's for sure. It may well
be the last statement of a transaction because of the implicit commits
(and yes there are two of them not one) but the use of the word
"required" leaves me uncomfortable with what the OP intended.
--
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)
Received on Fri Nov 19 2004 - 18:53:28 CST
