Re: Transaction logging without BEGIN WORK's

In article <6s7a59$eu8$1@news.xmission.com>, Jonathan Leffler <jleffler@informix.com> wrote: > > On Fri, 28 Aug 1998, H wrote: > > I have always been part of a project that involves starting a database > > with a transaction log and then coding programs with BEGIN WORK, ROLLBACK > > WORK and COMMIT WORK to (hopefully) keep the database as resilient as > > possible to any problems that might occur during processing. > > Good. > > > However, the database I am now working with has no transaction log > > associated with it and none of the 130 or so programs that interrogate it > > have any BEGIN WORK's etc...This strikes me as lunacy since it becomes > > difficult to maintain database integrity. > > Bad. > > > I was speaking to the guy who originally developed the application and he > > tells me that the database did originally have a transaction log but that > > the programs were not coded with BEGIN WORK's etc...but that did not > > matter. He said that if the system crashed they could still recover. > > Well, if they had a recovery plan, maybe it didn't matter. I'd have some > doubts about the recovery plan, but if they had a viable plan, it should > be OK. > > > I am a little unsure about this. I thought that if the database had a > > transaction log you had to code programs to commit or rollback > > transactions as necessary and then in the event of a system crash you > > can be sure that a roll forward or rollback would work successfully. > > It depends on the logging mode. In a MODE ANSI database, then you would > have to explicitly code the COMMIT WORK operation or any changes you made > would be rolled back when the program terminated. > > In a non-ANSI database, if you do not start an explicit transaction, each > separate statement is a separate transaction. This is essentially treating > the logged database the same as an unlogged database -- you have to go to > the recovery plan to recover if the system crashes after (say) 5 of the > necessary 7 updates have been completed. > > > Is what he saying is this - that be having a transaction log with > > coding the 4GL's with BEGIN WORK's etc then EVERYTHING is logged and > > that your only option after a crash is to ROLLFORWARD everything?? > > I don't understand this question. > > Yours, > Jonathan Leffler (jleffler@informix.com) #include <witticism.h> > Guardian of DBD::Informix v0.60 -- http://www.perl.com/CPAN > Informix IDN for D4GL & Linux -- http://www.informix.com/idn > > I think if in a database not exists a transaction control is impossible to guarantee a fully integrity in a database. All controls would be manuals but no automatics. It's necessary making a transaction definition using the BEGIN WORK, COMMIT WORK AND ROLLBACK WORK statements This is a -----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum