[camelx]

When I have been referring to new records, I was talking about the ebooks that were being added, and previously existing records are the ones that are in the database prior to adding the new records. Both become duplicates when added, sorry I wasn't so clear. So back to my quick scenario of adding 4 new records that already exist in my database.

1) When I add the four new books, I want to keep all their metadata and book formats - yes they will be new records
2) they will be duplicates with the previously existing four records records that were already in the database
3) All I want to have done now is merge all book formats from the previous existing that do not exist in the new records.

Example:

In my database I have the Space Odyssey series, four books -
2001, 2010, 2061 and 3001 - they all have existing metadata for this example I'll call "old metadata", with book formats of epub and mobi

I'm adding four new Space Odyssey books I purchased online -
2001, 2010, 2061 and 3001 - I want them to come in as NEW duplicate records keeping their "new Metadata" and the keeping book format of epub
(EVERYTHING stays with the new records that are added. The only things that is done for merging is bringing the mobi format into the newly added records because this did not exist in the newly added records. The new records has all their new meatadata and their epubs and now the merged mobi format from the previously existing records. Then delete the older previously existing records)

They only work at this point for Calibre is:
1) identify that these are duplicate records
2) compare book formats of the newly added records with the previously existing records and
3) ONLY merge Book formats from the previously existing records that did NOT exist in the newly added records into the newly added records.
4) Then delete the previously existing records

I end up with no duplicates.
My four Space Odyssey books 2001, 2010, 2061 and 3001 have all the metadata of the newly added records, the new epub from those newly added records, and finally the merged in mobi format from the older existing records. The older existing records are deleted after pulling out the mobi format.