[camelx]

This may be a request for new functionality, unless someone chimes in to show me how I can do this.

What is needed -

The ability when adding new books to keep the new book metadata and all it's book formats, but when duplicate books are found in the existing library, then ONLY pull book formats that do not exist in the new records.

Why would we need this -

there are times when I want to add new books where I know the metadata is better and maybe the book formats are cleaner than I had, but I don't want to lose a format I had in the existing records that is not in the new record.

Another example is where I buy a new series of books that have the series perfectly setup, I have duplicates of those books, but the series is all messed up. The new books I'm adding are only epub and my exisitng books with messed up series is mobi. I want all the metadata from the new books I'm adding to be what I end up with and merge the mobi from my duplicates.

What I have to do now to accomplish this -

simple example:
I want to add the perfectly structured Authur C. Clarke's Space Oddessy - 4 books.
I have existing 4 books in my library but series is not there, the covers are older and a lot of metadata is missing are not right, titles namescontaining series, etc. The existing format is mobi and some have epub, but they are many years old and those epubs are not all clean.

the new books I'm adding are perfectly formatted, series are named right and in order, covers are up to date and all metadata is much cleaner and format is epub, the epubs are formatted much better.

1) I add the new books (without automerger, to preserve the older records to get their epub formats manually). I now have four duplicates.

2) I right click on a new added book, series 1, and select similar books by author - only Authur C. Clarke books showing to keep it easy to work with.
3) I sort by series (my four new books are together)
4) I highlight the first book in series, then click the title column heading to sort by title. (this shows my first book in series right next to my existing book, 2001 in this case - new clean record and old record)
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5) THIS STEP is my main goal in my manual process - MY new record, series 1 book is highlighted and holding the control key, I highlight the existing old duplicate book). This now keeps all the metadata of new book and epub of new record, and adds only the mobi format from my old record and deletes that old record.
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Please don't say I can highlight the old records and easily edit in bulk the series, or use the series manager, etc. I know that. I also know I could bulk update with download covers and metadata.

The above example was a very simple example. A common case is where I will be adding a couple thousand books with many series updates, better metadata, cleaner formatted books, etc.

Bottom line of goal -

I want to use everything the new book record has - metadata and book formats and ONLY add missing book formats of DUPLICATE records to the new record and delete the old record.

My proposal for new Calibre enhancement -

Preferences/adding books
checking the: automerge books if they already exist in the Calibre Library
add a new drop down: "Keep the new record metadata and formats and add only missing formats from duplicates".

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Thanks for bearing with me on this. If I'm totally missing a way to do this, I'm sorry and please inform me. I really doubt I'm alone on this. I think this would be a powerful feature as a lot of us have library full of old records that could be cleaned up with such a feature. I hope Kovid will consider this!!!