[OAI-implementers] Deleted records

Alan Kent ajk@mds.rmit.edu.au
Fri, 8 Nov 2002 11:41:16 +1100

On Thu, Nov 07, 2002 at 09:27:28AM -0500, Steve Sarapata wrote:
> Is anyone supporting deleted records? If so, could you forward me some
> information on how you are handling these and also any issues you have
> faced?

Like Stuart, we keep a flag in the records to indicate whether deleted
or not. (I think we ended up calling the field 'obsolete' as it
got too confusing when talking about 'deleting' records - since in
some databases you really did delete the record and others it was
just marked as logically deleted.)

To save space, we discarded the record content (we use variable length
records) but we kept the date/time stamp. It is theoretically possible
in one harvest to get a delete, insert, and delete for the same record,
where the order of the operations is not sorted by date/time. So you
need to compare the date/time stamp of the new record and compare to
what you have in your local database to work out if you should really
delete or undelete the record or not.