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Resolved Deleting records from .DBF file from PowerBuilder

  1. How-to
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  1. Simone Olianti
    Simone Olianti
  2. PowerBuilder
  3. Monday, 13 May 2024 16:29 PM UTC

Hi everyone, I need to manage a .DBF file which is exposed from a PLC machine on a shared folder.
I found the way to handle it using the default Windows dbf ODBC driver.
The content of the file is retrieved correctly by PowerBuilder, but when I try to delete a record or truncate the table, it doesn't seem to work.

I've created a datastore to handle this file, everything seems to work wothout errors, but after a delete and commit, all the records are still there.
Insert seems to work correctly.

Unfortunately i havo no experience about .dbf files so i'll try here if anyone have some hints.

tia,

simone

Retrieval argument version difference
check external file timestamp
Accepted Answer
mike S
mike S Accepted Answer Pending Moderation
  1. Monday, 13 May 2024 17:26 PM UTC
  2. PowerBuilder
  3. # Permalink

 

dbf  'delete' does not remove the records.  it marks them as 'deleted'.  may be an option in the odbc connection on whether you can see 'deleted' records.

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Simone Olianti
  1. Simone Olianti
  2. Tuesday, 14 May 2024 07:10 AM UTC
thanks mike, to make it work i had to check even "exclusive"
  1. Helpful
Andreas Mykonios
  1. Andreas Mykonios
  2. Tuesday, 14 May 2024 08:41 AM UTC
Wow... 30 years ago we had to use pack! :-) I had forgot that... DBase III, DBase IV and Clipper... Lost memories...

Andreas.
  1. Helpful
mike S
  1. mike S
  2. Tuesday, 14 May 2024 21:22 PM UTC
I only remembered because i stole the idea. i recently built an in-memory database for key/values (using datastores) and i needed to be able to delete values and 'rows' (groups of key/values). Its a bit complex, but in essence, marking a row with a delete flag and then ignoring it ended up running a lot faster than actually deleting a row.
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Responses (2)
Chris Pollach @Appeon
Chris Pollach @Appeon Accepted Answer Pending Moderation
  1. Monday, 13 May 2024 16:41 PM UTC
  2. PowerBuilder
  3. # 1

Hi Simone;

  That could be because ...

  • File is write protected
  • You do not have write privileges to the shared folder
  • There is a Windows "Policy" setting blocking you.

Food for thought 

Regards ... Chris 

Comment
Simone Olianti
  1. Simone Olianti
  2. Monday, 13 May 2024 16:46 PM UTC
Hi Chris i've double checked but the file is not write protected.

I've also tried to copy it on a local folder of my working machine, and still fails. The funny part is that if i try to insert new records, it does work. Looks like only delete won't work
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Chris Pollach @Appeon
  1. Chris Pollach @Appeon
  2. Monday, 13 May 2024 17:03 PM UTC
If it does not with a local DBF file, then it could be your odbc driver.
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