[AccessD] Overwriting open Mdb

Henry Simpson hsimpson88 at hotmail.com
Tue May 27 11:17:33 CDT 2003


List:

A client of mine experienced a problem that I cannot reproduce.  A WAN 
connected user was taking an offisite copy of an Access 97 mdb file from one 
server to his local drive and accidentally pasted the file to the primary 
file server in yet another remote office.  This happened last night at about 
7:30 PM and although the office is usually closed at that time, there was 
one user who had a front end application open that had a live connection to 
the data mdb and an ldb file that named all users who had been in that day.

The file server on which the data file is located is an NT Server and the 
folder on which the data was located is accessible only to users of the 
application.  I received panic phone calls at 7:30 from the person who 
accidentally pasted the file and from the user who was on.  Neither was able 
to work with the data from their applications.

I was able to connect via dial up to a Terminal Server session and 
determined that the file size and date time stamp of the primary data file 
matched the back up file server indicating that the file had been copied and 
overwritten the live and open data file.  The ldb file revealed all users 
who had been on during the course of the day were still present verifying 
that the data file had been open at the time of the overwrite.  I was able 
to delete the ldb file and replace the data file with a backup.  
Fortunately, the system makes a hot copy of the data file to two different 
remote servers and to a synchronization folder on the primary server and 
this happened at 5:45 which is 45 minutes after the office usually closes.  
Relying on the daily tape backup would have meant significant data loss but 
in this case, there was only one user whose edits were impacted and he was 
aware of the loss and able to rekey it.

Had the data file been overwritten while no one had the file open, there 
would have been no indication of a problem and any edits after 5:45 would 
have been lost without notification as the user was attempting to take the 
synch copy from the server and it was recent enough that the data loss may 
have gone unnoticed.

What my question is, and what I can't replicate is, I am unable to overwrite 
an mdb file while it is open.  I tested this several ways today.  While the 
front end is open, a persistent global connection to the data file exists.  
No matter how I tried, with and without dirty records in the back end, while 
a front end was open, I was unable to deliberately overwrite the data file.  
That the file system allowed, or appeared to allow the overwrite last night 
is certain as the file size and date time stamp matched the synch and remote 
server copies exactly.  The file size also indicated that the file had been 
saved in the backup copy compacted state as it is typically about 20% larger 
at the end of each day.  I took a copy of the apparently overwritten file 
before replacing it and it is irreovcably, with the limited tools we have at 
hand, corrupt.  If I can't deliberately overwrite the open file, how could a 
user have done it accidentally?

Hen

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