Home » Developer & Programmer » Forms » need_a_roll_back_mechanism (Forms [32 Bit] Version 10.1.2.0. win xp)
need_a_roll_back_mechanism [message #497265] Fri, 04 March 2011 12:48 Go to next message
m_shehpar
Messages: 73
Registered: October 2010
Location: Pakistan
Member
hi all,

in a when timer expire trigger (after a when validate record) i have prompted the user to save the record otherwise his record will be
rollbacked...
--------------------------------------------------------------------------------
IF SHOW_ALERT ('SAVE_CHANGES') = ALERT_BUTTON1 THEN
COMMIT;
ELSE
rollback;

--------------------------------------------------------------------------------

"if" part works fine but when the else part is executed another built in PROMT/ MESSAGE is popped asking to choose YES/NO/CANCEL for the change to occur which is against my interest... plus the whole form is cleared after rollback... i want to do all this via my own alert buttons and dont want my entire form or the block to be cleared when the trigger fires for a particular record


can anyone help me to escape this situation???? or give me an equivalant logic...

regards


i use Forms [32 Bit] Version 10.1.2.0.2 (Production

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Re: need_a_roll_back_mechanism [message #497281 is a reply to message #497265] Fri, 04 March 2011 13:38 Go to previous messageGo to next message
Littlefoot
Messages: 21818
Registered: June 2005
Location: Croatia, Europe
Senior Member
Account Moderator
Personally, I think that what you are trying to do is wrong. Forms has its own mechanism that warns users to save changes they made before leaving the form.

Why would you rollback a record, anyway? If someone put some effort into entering those values, let him/her decide when to commit (or not). If you want every record to be saved, why don't you simply COMMIT after user navigates into a new record?

Anyway: as far as I can tell, ROLLBACK will clear the whole form and there's nothing you can do about it. Instead of rollback, you might simply CLEAR_RECORD (if you insist on doing that job).

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Re: need_a_roll_back_mechanism [message #497449 is a reply to message #497281] Sat, 05 March 2011 11:38 Go to previous messageGo to next message
m_shehpar
Messages: 73
Registered: October 2010
Location: Pakistan
Member
hi little foot,

i want to save the record after each record validation cuz i have formulated a mechanism to keep my auto advancing number (componint_no) automatically advancing...

in validate record i have written like:


IF :SYSTEM.RECORD_STATUS <> 'QUERY' THEN
SELECT MAX(componint_no)+1 INTO :blood_bank.componint_no FROM STORE
WHERE branch_id = 'HBFP';
:BLOOD_BANK.BRANCH_ID := 'HBFP';
vTimer := create_timer ('SAVE_REC', 100, NO_REPEAT);
END IF;


in when timer expire i have written:

IF vcTimer = 'SAVE_REC' THEN
IF SHOW_ALERT ('STORE_INS_SAVE') = ALERT_BUTTON1 THEN
COMMIT;
ELSE
ROLLBACK;
--PREVIOUS_RECORD;
--DELETE_RECORD;
END IF;



----------------------------------------------------------------

--PREVIOUS_RECORD;
--DELETE_RECORD;

this logic deletes the record even when an update is inteded to be rolled back, thus a saved record is lost...

whereas rollback statement does the desired job but it issues its own prompt too, (in addition to my own alert, as you could see in the when timer expire...) asking YES / NO / CANCEL and then clears the whole form...


can you people rectify this logic for me???. i dont want to use sequence for a number of relevant personel issues, so please
give me some other logic, if you have on your mind...

waiting eagerly

regards....

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Re: need_a_roll_back_mechanism [message #497550 is a reply to message #497449] Sun, 06 March 2011 02:09 Go to previous messageGo to next message
Littlefoot
Messages: 21818
Registered: June 2005
Location: Croatia, Europe
Senior Member
Account Moderator
"MAX + 1" is a wrong mechanism in multi-user environment, because (sooner or later) two users will fetch the same "MAX + 1" (because, the first user won't commit yet, so the second one will get the same value. Then, when both of them commit, one will get the "duplication" error message). If the whole logic you developed is about gapeless sequence numbers, perhaps you'd want to read this discussion.

As of Quote:
this logic deletes the record even when an update is inteded to be rolled back, thus a saved record is lost...

I think that you got it wrong. All changes you store into the database (using the COMMIT statement) can not be rolled back. True, form will be cleared, but - if you execute query - you'll fetch those records.

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Re: need_a_roll_back_mechanism [message #497795 is a reply to message #497265] Mon, 07 March 2011 04:07 Go to previous messageGo to next message
mehediu
Messages: 46
Registered: February 2010
Location: Dhaka
Member
You can use Issue_rollback(null) instead of rollback;

may be it can help you.

thanks
Md. Mehedi Hossain

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Re: need_a_roll_back_mechanism [message #497802 is a reply to message #497795] Mon, 07 March 2011 04:44 Go to previous message
Littlefoot
Messages: 21818
Registered: June 2005
Location: Croatia, Europe
Senior Member
Account Moderator
Before applying ISSUE_ROLLBACK, Shehpar should read Help. It says that ISSUE_ROLLBACK is meant to be used in applications that run against a non-Oracle data source (which is not the case). It also says that results are unpredictable when it is used outside an ON-ROLLBACK trigger (which is the case here).

So ... I'm not sure it'll help much.

Also, perhaps it wouldn't hurt to read this Experts exchange discussion (scroll down, to the bottom of the page) (pay attention to the first schwertner's message).

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