• Subject: Re: Retrieving deleted records
  • From: dhandy@xxxxxxxxxxx (Douglas Handy)
  • Date: Thu, 14 Oct 1999 15:07:56 -0400


>Is there a way to retrieve a deleted record without having to copy the
>entire physical file to the save file and reading through the save file.  It
>would be really nice to be able to retrieve a deleted record by key.  I know
>there are some products out there that allow this, but was wondering how
>hard it would be to write in-house.

You can't retrieve a deleted record by key, or at least not directly.
They have to be retrieved by RRN.  The only way you would have a
pseudo-key retrieval would be by sequentially checking the records
till you had a match on the key field(s).

How hard it would be to write in-house depends on how well versed you
are with MI.  You can't do it directly from a HLL, except via the SAVF
technique.  But why bother?  Dave McKenzie has graciously put his
UNDEL in the public domain, including the MI source.  Or you could
just call his MI program with the right parameters and put your own
interface on it if you didn't like his.

That is what was done with WRKDBF, which also supports undeleting
records.  It uses McKenzie's routines under the covers.  The v07
release of WRKDBF only allowed undelete of non-keyed physical files,
but the newer v08 release allows it on keyed files as well.

You may want to check out both of these utilities -- they are free.
The UNDEL source and objects for both RISC and CISC can be found on at
www.news400.com under Resources | Code | Freeware, and the latest
WRKDBF can be found for both RISC and CISC at www.wrkdbf.com.

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