Re: recovering deleted records

[PaulMmn <PaulMmn@xxxxxxxxxxxxx>]

>How does DBU's product "RDR" accomplish this task?

In brief--

When a record is deleted from a file, as long as the file is NOT
reusing deleted records, and until the next reorganize of the file
(RGZPFM), the record is NOT really gone!  It's just been flagged for
deletion.

When you use RGZPFM, the live records are all squeezed down to one
end of the file, and the deleted records are at the other, and
available for (re)use.

When you save/restore a PF, all of the records go along for the ride.
Including the ones flagged for deletion.

What these programs do is save the file to a save file.

A save file can be read in an RPG program.

"Simply" read the save file, and copy the resulting data to a new
file with the same attributes of the original.  The deleted records
are flagged as deleted, the live records are not.

The tricky part is that the record length of the save file (RECL 528,
IIRC), will probably NOT be the record length of your file!  Plus,
the save file has some additional bytes sprinkled here and there
(notably the live/deleted flag; there may be others).  You'll have to
buffer the input file and re-assemble the pieces of your records.
[Some of your records will span more than 1 record in the save file]

That's the key.  I haven't tried DBU's method with a real file; Does
it need equal space to the original?  What happens if it's a HUGE
file??

  I don't know if there's another way to get at the data other than
thru a save file.  Is there an API?  I haven't checked.

--Paul E Musselman
PaulMmn@ix.netcom.nospam.com