Re: dbf trashing problem after upgrade

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hi edhy,

are you suggesting that i should set - for example - the table property to
use buffering and after saving all changes do a table update ? do you think
that not doing so (ie commiting changes with insert or gather memvar and
then a flush command) will eventually lead to data corruption whenever a
failure occurs ? also what do you think of anders' suggestion of using FLUSH
FORCE or SYS(1104) ?

thanks

"Edhy Rijo" <erijo@xxxxxxxxxxxxxxx> wrote in message
news:u8wmcYyOFHA.3444@xxxxxxxxxxxxxxxxxxxxxxx
> Hi Anis,
>
> You should have done a re-write using the new features of VFP7, it seams
> to me you are treating VFP7 as FPW26 and that may work in some situations
> but in a POS application where there is an intense data entry and on a
> network, you should use the new buffering of VFP7. Make sure you are also
> using the latest service pack for VFP7. Don't use browse windows, instead
> use a grid and better yet start using local views, at the end it will make
> your life easier and safer. Use your FPW26 expertise to re-learn VFP7
> and/or VFP9 is possible and redo the project, you will not regret it and
> it will be easier to maintain and add new features only possible with new
> versions.
>
> I have a POS system created first in VFP5 and upgraded to VFP8 and like
> you I used to use FoxFix a lot with FPD26 but after VFP6 I stopped using
> it because the data corruption was totally suppress on my customers, of
> course they all have an NT Kernel Server from Windows 2000 (That is a
> requirement of my software) and for workstations a mix of 98 to XP (Me is
> not supported, too buggy <s>).
>
> --
> Edhy Rijo
> www.progytech.com
> Bronx NY
>
>
> "Anis" <anis@xxxxxxxxxx> wrote in message
> news:OLeGYBtOFHA.2704@xxxxxxxxxxxxxxxxxxxxxxx
>> hi craig,
>>
>> i think i got this idea accross wrongly. i use modal forms and scatter
>> memvar to memory variables. after that i either use insert into <table>
>> from memvar to insert or gather memvar memo to update. after that, i
>> issue a flush after each insert or gather memvar. this worked perfectly
>> with fpw26 and the application recovered very well from crashes without
>> any garbage in the dbfs but now the exact opposite occurs although i am
>> using vfp7 sp1 and now running the app on xp. quite weird.
>>
>> thanks
>>
>>
>> "Craig Berntson" <iamcraig@xxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:ep%23sNhrOFHA.580@xxxxxxxxxxxxxxxxxxxxxxx
>>> The application does exactly one of the things that is very likely to
>>> cause corrupt data...writing directly to the table. Buffering greatly
>>> helps to resolve this problem. I have rarely seen data corruption due to
>>> the application since I started using buffering.
>>>
>>> Note there are other things that can cause data corruption. Some are
>>> listed at http://www.craigberntson.com/Articles/kb005.htm
>>>
>>> --
>>> Craig Berntson
>>> MCSD, Visual FoxPro MVP
>>> www.craigberntson.com
>>> Salt Lake City Fox User Group
>>> www.slcfox.org
>>> www.foxcentral.net
>>>
>>>
>>> "Anis" <anis@xxxxxxxxxx> wrote in message
>>> news:%23t$fl5pOFHA.3000@xxxxxxxxxxxxxxxxxxxxxxx
>>>> greetings to all,
>>>>
>>>> we have been loyal foxpro users for 12 years now and have developed
>>>> various point-of-sale applications by using forpro 2.6
>>>> for windows. our pos applications run on windows 98 se and in most
>>>> cases run in a network environment with at least 3 users
>>>> and above. due to the nature of foxpro dbfs and the serious issue of
>>>> dbf files being trashed which especially occurs when the
>>>> ups system goes down unexpectedly or when the server (also a win98 se
>>>> machine) crashes, we extensivley used foxfix to remedy
>>>> any issue automaticallty from the software and things seemed to work
>>>> great 99.99% of the time all in all resulting in a very
>>>> stable and recoverable application that made our clients very happy and
>>>> our support staff glad.
>>>>
>>>> last year, we converted one of our pos applications to vfp7 sp1
>>>> (running on windows xp) and since we were loyal foxfix users,
>>>> we purchased foxfix 5.2 in order to obtain and attain the reliablity
>>>> which we were accustomed to from the marriage of fpw26
>>>> and foxfix in our suite of applications. but things now seem to have
>>>> changed. any time a crash occurs - for example the ups
>>>> system goes down - foxfix is able to make all dbfs usable after a total
>>>> system restart, but now opening any dbf file which is
>>>> updated extensivley by the application (the sales file for example) and
>>>> setting the order to the primary index tag yields
>>>> tons of trash records at the beginning and the end of the dbf in the
>>>> browse window. this case almost always happens when any
>>>> crash of either the ups or the server occurs. what surprised us is that
>>>> this EXTREMELY RARELY occured with our old version!
>>>> what is also funny is that in most cases, no data seem to have been
>>>> lost (except for the cases of partial record trashing),
>>>> only garbage gets appended to or inserted into the dbf from an unknown
>>>> source.
>>>>
>>>> We have reused 95% of the code in our old application and the business
>>>> logic is still the same. we do not use any buffering,
>>>> or transaction tracking. all updates to the dbf are directly written
>>>> followed by a flush command in the unload method of each
>>>> form - the same way as we used to do before. also, we use the same data
>>>> session for all the application and all dbf files are
>>>> opened at the start of the application and are closed when the
>>>> application terminates.
>>>>
>>>> when you upgrade a development platform, you expect all the niceties
>>>> and advantages and reliability that comes with the term
>>>> UPGRADE. what you dont expect is going a couple of steps back with an
>>>> upgrade of at least 4 versions forward (fpw26 to vfp7),
>>>> and at least 2 upgrades forward for the os (win 98 se to winxp). but
>>>> then again, we might have made a mistake somewhere.
>>>>
>>>> i would appreciate any help or feedback regarding this issue and i
>>>> thank all those who reply to this post in advance for
>>>> their help and for sharing their experiences.
>>>>
>>>> regards
>>>>
>>>> anis
>>>>
>>>>
>>>
>>>
>>
>>
>
>


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