Re: File field maintenance logging

On Fri, 2014-08-01 at 12:51 +0000, (WalzCraft) Jerry Forss wrote:

Hi All,

I want to create a "new" standard here in which all access to a file (Inquiry and Update) are done through a single pgm.
Let's call it FMMasterR for file MASTER.
My display pgm gets the record from FMMasterR. It is maintained and returned to FMMasterR as a DS (Parm_DS). I chain to MASTER receiving it into a Old_DS. I can compare Parm_DS to Old_DS to see that something changed. I can get the field names in the file easy enough loading into an array. What I want to do spin through the fields finding what changed. Something like
If Parm_DS.Field(1) <> Old_DS.Field(1). I then can write to a maintenance log of specific field changes. I know someone does field level maintenance logging so I am looking for some guidance on the best approach. Being I have the fields, length and pos I suppose I could try and compare doing a substring on the entire length of the file.
I am just playing and trying to come up with some ideas.

Actually you would need to store 3 versions of the record, as the above
doesn't take into account "retrieve record, go take a smoke break, amend
record, push changes to file (and audit log)" where record level locking
is _not_ used.

FMMasterR retrieves record, and stores it in 2 structures (beforeDS,
editDS)
FMMasterR returns editDS.
Aprogram modifies editDS and returns it to FMMasterR
FMMasterR retrieves record again into liveDS and compares it to beforeDS
if beforeDS and liveDS don't match then record has changed since
original retireval; at this point its upto you as to how you deal with
the problem.

Using field level comparisons of liveDS and editDS its possible to push
some changes to the file where this would not cause an issue, or prevent
the whole update where such a change would overwrite an already modified
record... adding or subtracting to a stock value "probably" would be ok,
but blindly changing it to a fixed entry value "probably" would not (as
a rough and ready example).

My gut feeling would be to use journaling as an audit method, its simple
and works very well (if potentially somewhat high on storage space) and
has the advantage of auditing "backdoor" changes that for what ever
reason didn't go through FMMasterR (dfu, odbc, sql, some long forgotten
program that shouldn't be used but happens to still be accessible from a
menu somewhere).

Thanks!!