Opening Excel Files from DB (blob column)

Question

My project has implemented a WEBUTIL solution to attach files into the database, view the files stored in the database (in a BLOB column), and remove the files stored in the database.
Everything has been running smoothly. We are in final testing and have found a couple of interesting scenarios ...
When a user tries to view an Microsoft Excel 2007 file from our application, the Excel file displays properly (as long as Microsoft Excel isn't already open - outside of our Oracle application). Once the Excel file is viewed, the system will not allow the user back to our application until after the Excel file is closed (we use the start /wait myExcelFile.xls ... command). This works perfectly for us.
The two scenarios we encounter occur when
1.) The user has Microsoft Excel open outside of our application and tries to open an Excel file from within our application, or
2.) The user has the file already open (either from within our application or outside of our application) and then tries to open the file from within our application.
Let me explain a little further because the above two scenarios are interrelated.
When a user has Microsoft Excel open (outside of our application), and then clicks the button to open the Excel file, the system will open the file as another window (within Excel). The system will allow the user to navigate back to our application (where as, if Excel is not open outside of our application, the system will not allow the user to navigate back to our application). Once the user navigates back to our application (while the file is still open), the user can click the button to view the file again. At this point, the user is displayed a WUT-105 error message (I assume b/c the system is trying to open a file that is already open).
I assume the two solutions are the following:
a.) Do not allow a user to open a file that is already open (not sure how to check this from within Forms ?)
b.) Do not allow a user to open an Excel file when another EXCEL process is already running (this will avoid allowing the user to naviagate back to our application)
I don't know if there is a better solution.
Do you experts have any recommendations?
We are using Oracle Application Server 10g R2 (10.1.2.0.2), Oracle Database 10g R2 (10.2), and Oracle Developer 10g (10.1.2.0.2)
I hope this all makes sense.
Thanks,
Mike
Edited by: user639843 on Oct 20, 2008 2:15 PM
Edited by: user639843 on Oct 20, 2008 2:20 PM

Answer 1

Thank you, Thank you, Thank you!!!!
I believe that will work (adding a sequence number to the end of the filename)!
We do not allow a user to update the file, only view. If a user wants to make a change, they need to remove the existing file (from the database), create a new file (outside of our application), and attach the file in our application (into the database). All updates occur outside of our application - we are not a document authoring system, just a document storage system.
Once again, many thanks on the solution!
Mike