Lost Data

[GeorgeMar]

I have been developing in Access for over 20 years and this is the first time
that I have heard the users complain of data loss ( I haven't witnessed it
yet). Beacuse it has happened several times and to different users I do not
doubt the voracity of their claims.

My application is distributed to 40 different customers and have never
experienced data loss until now.

Details:
Front End: Access Mde 2003
Back End: Access Mdb 2003
Workstation O/S: XP
Server: MS Server 2003

Here are some of the experiences:

Network is sometimes slow.

One user account is extremely slow no matter where she logs on. Other users
with different accounts are fast on teh same workstation.

When data is entered by one user, it can be seen on that user's screen but
the newly entered data cannot be seen by other workstations. They have even
shut down and restarted to no avail. Sometimes, two worksations can see the
newly entered data and a third one cannot. They have printed off reports of
the entered data with date stamps and within minutes the data is lost. The
data is not in the relevant table. However, there are days where there no
data loss.

There is obviously only one Back End. It sometimes looks like some of the
users are in a different Back End, as if MS has created a snapshot and then
not save it. That doesn't sound right but just an impression.

Has anyone encountered this before? I am desperate for any help.

regards
George

 

[Jeff Boyce]

Uhm, ... some days it feels like it's been that long to me, too <g> ... but
Access 1.0 showed up in 1992, so "over 20 years" is a ... colorful way to
put it.

Can you confirm that the data is actually lost (i.e., missing from the
table)? Or is there a chance that folks aren't seeing it (due to filtering,
querying, ...)?

The data is on a LAN (or are users accessing it over a WAN?). Is the
"front-end" also on the LAN?

More info, please...

Regards

Jeff Boyce
Microsoft Office/Access MVP

 

[GeorgeMar]

My apologies

It feels like 20 years. I have been developing databases for over 20 years
but Access since Access 2.0. You're right!

1. The data is definitely not in the table
2. The application is on a LAN
3. The FE is on every local drive linked to the BE on the server

Someone asked me to ask the LAN manager to look at Antivirus and also the
possibility that RAID could be deleting data that it deems to be a threat.

Any further suggestions welcomed.

George

 

[Jeff Boyce]

Some days like more than 20!

Have you made backup copies of both FE and BE, then run Compact & Repair?

Regards

Jeff Boyce
Microsoft Office/Access MVP

 

[Jack Cannon]

George,

My database design experience goes back even longer than yours and during
that time I have experienced three incidents similar to your description.

1. An employee figured out a way to bypass the security mechanisms and
overtly deleted all customer records.

2. An employee with the security level that granted access to certain
records deleted arbitrary records for the purpose of making the company look
bad so that a competitor friend could move in and get the contract.

3. The owner of the company working in the database window thought that
they could copy and paste a link to a table within the database window for
the purpose of deleting certain records supposedly without harm to the
database. They did not understand that they only copied the link - not the
actual table. Since that incident I have been granting owners the lowest
level of security - not the highest.

You might have to implement a mechanism that saves deleted and perhaps
edited records along with the userid and date/time stamp of when it happened.
This is easy to do if you have SQL Server as a backend. If Access is the
backend then it takes a little more effort. If edited records are saved it
can also cause the database to get very large very fast which may cause you
to occasionally have to move the records to some form of an archive.

Such a CYA mechanism can prove worthwhile when your client informs you that
the missing records or improper data are clearly a fault of your program
because their employees are all too smart to cause such problems.

Jack Cannon

 

[GeorgeMar]

Thank you Jack.

I will keep that in mind. However, I think that in my situation ther server
is doing some "funny" things. Last week, data entered by one user could only
be seen by that user and not others; as if there are multiple instances of
the application running.

George

 

[Stefan Hoffmann]

hi George,

Details:
Front End: Access Mde 2003
Back End: Access Mdb 2003
Workstation O/S: XP
Server: MS Server 2003

Ensure that all clients have the same Office Version including the same
service pack and hotfixes installed. Check whether they have the same
MDAC/Jet, the same AV.

Network is sometimes slow. http://www.google.de/search?q=access+improve+performance&btnG=Suche&meta=lr=lang_en


When data is entered by one user, it can be seen on that user's screen but
the newly entered data cannot be seen by other workstations.

Does the data entry require a separate save action from the user?

Sometimes, two worksations can see the
newly entered data and a third one cannot.

Do you filter data per user (settings)?

There is obviously only one Back End. It sometimes looks like some of the
users are in a different Back End, as if MS has created a snapshot and then
not save it. That doesn't sound right but just an impression.

Where is the BE stored? Does a rollback to a shadow copy occur?

Has anyone encountered this before? I am desperate for any help.

Not with these symptoms.



mfG
--> stefan <--

 

[GeorgeMar]

Thnk you all!

I have found the culprit.

The client has two servers running concurrently using DFS (Distributed File
System) between them. The idea was that if one server goes down, the other
would continue to operate as normal. DFS (in my understanding) copies the
user's data at regular intervals to the backup server and vice versa (and
that is the problem).

However, that replication was not hapenning fast enough which meant that
some users were seeing different data and some were losing their data. That
is my explanation, there may some more accurate explanations for what is
going on.

The end result is , the shared folder containing the Back End database was
moved out of the DFS and evrything worked as it should.

many thanks
George