Synchronizing the Volume and Table Information [Revelation On-Line Wiki]

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====== Synchronizing the Volume and Table Information ======

Code similar to the following is used in OpenInsight to ensure that volume and table information is synchronized. You should never need to use this code, but it explains why a synchronization problem could cause a table to become unavailable:

<code>
* first verify volume structures

cVols = count(Volumes(0), @fm) + (Volumes(0) # "")

for iVol = 1 to cVols

  Vol = Volumes(0)<iVol>

  cFiles = count(Volumes(3)<iVol>, @vm) + (Volumes(3)<iVol> # "")

  for iFile = 1 to cFiles

    File = Volumes(3)<iVol,iFile>

    locate File in Tables(0) using @fm setting Pos then

      * check volume reference

      if Tables(1)<Pos> # Vol then

         Volumes(3) = delete(Volumes(3), iVol, iFile, 0)

      end

     end else

  * file does not exist but is referenced by volume

  Volumes(3) = delete(Volumes(3), iVol, iFile, 0)

  end

  next iFiles

next iVol

 

cFiles = count(Tables(0), @fm) + (Tables(0) # "")

for iFile = cFiles to 1 step -1

  File = Tables(0)<iFile>

  Vol = Tables(1)<iFile>

  * check volume reference

  locate Vol in Volumes(0) using @fm setting Pos then

    locate File in Volumes(3)<Pos> using @vm setting Pos else

      * file not referenced by a volume

      for i = 0 to 5

        Tables(i) = delete(Tables(i), iFile, 0, 0)

      next i

    end

   end else

    * file references unattached volume

    for i = 0 to 5

       Tables(i) = delete(Tables(i), iFile, 0, 0)

    next i

   end

next iFile
</code>