anomaly in synchronizing reader and libraries

[DrChiper]

Hi Kovid, I have a small question:

Having a pre-virtual library installment, I have multiple calibre libraries, one per book language (German, English, French, etc.).

It happens sometimes that I have a certain book available in more than 1 language (hence also present in multiple libraries), but I place only 1 particular language on my e-reader at a time.

When I select a certain library and then connect my e-reader synchronization takes place as it should.

Now, I noticed that, when in all (language) libraries the book also has the same title (yes, this happens...), synchronizing my e-reader results in a hit with ALL libraries in which the book is present, although the book (language) is different for all but 1 library.

Apparently during the synchronization the book language meta-data is not taken into account.

As I do consider to migrate to virtual libraries, what will happen then when I synchronize with my e-reader? Are books with identical titles but in different languages actual possible to synchronize and can calibre tell which book (language) really is present on the e-reader and which others are not?

[kovidgoyal]

There is no synchronization, simply an on device indication. That indication is based on the following criteria:

A book in the library is said to match a book on the device when:

1) The internal calibre library uuid matches
or
2) The metadata (title/authors) matches

If you have multiple books with the same title/author, they might well match multiple times, this is fairly harmless, since calibre does not actually do anything with the on device status, other than display it. So you will simply get multiple books being marked as on the device.

[DrChiper]

Ok, thanks for the clarification Kovid.

That said, what will happen if a book is said to be present on the e-reader (according calibre) and I want to send the same kind of book (same title/author, but with different language, hence other internal calibre library uuid) to the e-reader? Will calibre just allow this?

[kovidgoyal]

yes .

[DrChiper]

I'm sorry to say, but it does not work.
I just tried to add a book with the same title/author (but different uid) and different language to the e-reader and the already existing book is +replaced+ by the new one. So it seems that it is not possible to have +both+ books present via calibre on the e-reader.

Of course, I can add the extra book outside calibre, but that is not what I want (missing collection info, etc.).

Possibly there is some workaround?

[Adoby]

Place the two books in different subfolders on the device, or give the books different filenames. If the two books have the same filename and are placed in the same folder, then obviously one of them will overwrite the other.

[kovidgoyal]

Change the template for send to device to include the language field. Or give them different titles.

[DrChiper]

Hmm, although it is currently not a problem as I'm using separate libraries, it will be a problem when using one monolithic library and virtual libraries.

I see the following issues:

1. Adding books
   to allow same title/author books with different language, calibre must store them separately (per language), hence:
   calibre preferences -> Adding books -> Automerge added books -> Create new record for each duplicate format
2. calibre database
   add extra column with language indication for quick detection
3. sending to e-reader
   adjust plugin reader to have output file name now to include "languages"

This will cover everything sufficiently I think.

Unfortunately, "languages" does not appear in the "sending books to devices" variables list.
Will it then work with the plug-in directly?

[kovidgoyal]

You can use languages, it just isn't listed in the help list.

[Adoby]

Duplicate book entries in calibre is not a problem. Every book has a unique numeric ID added to the folder name, so there is no danger for any book overwriting another in the calibre database or in the calibre folder tree.

[DrChiper]

Thanks Kovid, works fine!
And "languages" produced a nice 3 char abbreviation (I feared for the long version)

@Adoby: correct. But when adding books calibre uses file name and/or some metadata to determine whether the book is already present. And as calibre seems not to use dc:language it is not able to distinguish similar books with only different language.