Custom Column side-effects

[botmtl]

I really like custom columns, but I'm not too keen on their side-effects. The side effect i'm referring to is that when the custom column data changes, then the book metadata.opf gets updated and the book is considered "dirty" (changed) for the sake of synchronisation.

For example, let's take one a lot of people have, author_book_count. When the book count is updated, all the books in the library will be updated. When I next synchronize with a device, all the books will need to be resent (as then have changed since the last sync).

Aside being a problem with syncs, is that some of those columns can contain private information that needs to be scrubbed if the file is ever to be shared (web content epubs for example).

I was wondering if there was any way (hidden tweak?) I could mark some columns as being "database only", i.e. that medatadata field wont be updated in the book files (and metadata.opf).

(not sure i'm being clear so this is another way to ask exactly the same thing) -> Is there a column filter setting that can be used to identify columns that are not to be written in the book's metadata?

[theducks]

I only know of the tweak: ID: content_server_will_display
(I thought there was also one for the Jacket, but I can't find it)

[DoctorOhh]

Originally Posted by botmtl

I really like custom columns, but I'm not too keen on their side-effects. The side effect i'm referring to is that when the custom column data changes, then the book metadata.opf gets updated and the book is considered "dirty" (changed) for the sake of synchronisation.

Making changes to calibre custom columns should not change any books in your library. The metadata.opf file in the book's directory within the calibre library will be updated because that is used for backup.

Originally Posted by botmtl

For example, let's take one a lot of people have, author_book_count. When the book count is updated, all the books in the library will be updated. When I next synchronize with a device, all the books will need to be resent (as then have changed since the last sync).

What device are you using and what program are you using to sync to that device? Some devices such as Android devices that use Calibre Companion will sync the changed metadata every time you connect to the device. Syncing the metadata is not the same as resending books. I have never had any books resent to my device because I updated a custom column.

Originally Posted by botmtl

Aside being a problem with syncs, is that some of those columns can contain private information that needs to be scrubbed if the file is ever to be shared (web content epubs for example).

I was wondering if there was any way (hidden tweak?) I could mark some columns as being "database only", i.e. that medatadata field wont be updated in the book files (and metadata.opf).

Again, the metadata.opf files in the calibre library's book directories is a non-issue since this file is used for backing up the library and used to reconstruct the database when needed.

Originally Posted by botmtl

(not sure i'm being clear so this is another way to ask exactly the same thing) -> Is there a column filter setting that can be used to identify columns that are not to be written in the book's metadata?

You're being clear. I think all metadata is written to the book when you send the book to the device. I don't know of anyway to selectively pick and choose which metadata is written to the device. I have never had any books on my device automatically updated whenever I change a custom column.

[DaltonST]

For example, let's take one a lot of people have, author_book_count. When the book count is updated, all the books in the library will be updated. When I next synchronize with a device, all the books will need to be resent (as then have changed since the last sync).

Actually, not true. The ABC plugin does a direct metadata.db update to the author_book_count custom column SQLite table, so it does not trigger any metadata.opf refresh. Nor should it. ABC is calculated, not a static reference metadata value. ABC also does not update the Last Modified Date for the same reason. ABC is Library-level at a specific point in time.

So, only metadata.db is changed. One file. Nothing else.


DaltonST

[BetterRed]

Originally Posted by botmtl

-> Is there a column filter setting that can be used to identify columns that are not to be written in the book's metadata?

I use the Modify plugin to strip non DC metadata elements, it follows that I also eschew the use of calibres Send to Device, Save To Disk, for they put it all back. But that suits me, I use an Android tablet, I manage all the data with one app (Cheetah Sync), and I only keep a current working set of 10-30 'books' on it.

Another possibility might be to copy the books in question to a fresh empty 'Output' library, only selecting the custom columns required when copying. And then send/mail/save the books from the 'Output' library. And then delete the 'Output' library and create a fresh one. But you'd lose any device syncing capabilities.

I like the idea of a feature to select what metadata is sent/saved, as well as all the non-DC elements I would also unselect Comments (DC:Description), and Tags (DC:Subject). Today I remove them with Sigil's metadata editor..

BR

[botmtl]

Thank you all for correcting me on several points for which I had assumed wrong.