Restore custom columns

[Sys_eng]

I successfully restored a library via
Library > Library Maintenance > Restore Database
but I stil can't see the custom cloumns. Any recommendations to restore the custom columns would be highly appreciated.

[theducks]

Did you destroy metadata_db_prefs_backup.json?
That was YOUR structure backup and should have been used as part of the restore

[Sys_eng]

No, i still have it, but I am not sure how I can use it.

[theducks]

Originally Posted by Sys_eng

No, i still have it, but I am not sure how I can use it.

It should have been used if it was in the normal place when you ran restore.
The issue now, is the metadata.opf backup file has been overwritten , losing the custom column info that was there.
Your only chance is if you Polished the books and embedded the metadata BEFORE your corruption. In that case, you can use the Metadata editor and fetch the books copy of the metadata
In bulk mode. Do only for books that you KNOW are correct. If the book is stale or wrong, that can ruin the better entry
tick Set Metadata from book files

[BetterRed]

Originally Posted by Sys_eng

I successfully restored a library via
Library > Library Maintenance > Restore Database
but I stil can't see the custom cloumns. Any recommendations to restore the custom columns would be highly appreciated.

Where did you look for them?

Check Preferences->Add your own columns.

BR

[Sys_eng]

Originally Posted by BetterRed

Where did you look for them?

Check Preferences->Add your own columns.

BR

I looked there and I can see the the 4 custom columns that I created checked (with a check mark).

[Sys_eng]

Originally Posted by theducks

It should have been used if it was in the normal place when you ran restore.
The issue now, is the metadata.opf backup file has been overwritten , losing the custom column info that was there.
Your only chance is if you Polished the books and embedded the metadata BEFORE your corruption. In that case, you can use the Metadata editor and fetch the books copy of the metadata
In bulk mode. Do only for books that you KNOW are correct. If the book is stale or wrong, that can ruin the better entry
tick Set Metadata from book files

Thank you for your response. I am new to Calibre. I was advised to restore the library via:
Library > Library Maintenance > Restore Database


Question Where the metadata.opf file is located? When I performed the respore, I had only 2 files in the library (1) metadata_db_prefs_backup.json and (2) metadata.db

and after the restore, I found 3 files (1) metadata_db_prefs_backup.json, (2) metadata.db (3) metadata_pre_restore.db

I am running Calibre on an iMac, and I have TimeMachine running all the time. (1) If metadata.opf is located somewhere other than the library folder, I will try to restore a previous verison of it. The only other folder associated with Calibre on teh operating system that I am aware of is the configuration folder (shown in the screenshot). In that folder, I could not find a metadata.opf

https://ibb.co/SKPg6br

(2) Question: I understand that Calibre is not designed for simultanuous access (therefore it's not recommneded to be hosted on a cloud service or NAS. Does that also apply to AppleTime Machine? i.e could Apply TimeMachine reuin the database?

When I looked at the metadata editor, I could not find the option "Set Metadata from book files" . Question: I would appreciate that you point me to it to give it a try.

[theducks]

Thank you for your response. I am new to Calibre. I was advised to restore the library via:
Library > Library Maintenance > Restore Database


Question Where the metadata.opf file is located? When I performed the respore, I had only 2 files in the library (1) metadata_db_prefs_backup.json and (2) metadata.db

and after the restore, I found 3 files (1) metadata_db_prefs_backup.json, (2) metadata.db (3) metadata_pre_restore.db

I am running Calibre on an iMac, and I have TimeMachine running all the time. (1) If metadata.opf is located somewhere other than the library folder, I will try to restore a previous verison of it. The only other folder associated with Calibre on teh operating system that I am aware of is the configuration folder (shown in the screenshot). In that folder, I could not find a metadata.opf

https://ibb.co/SKPg6br

Restore expects everything else (other than the corrupted DB) to be in the normal place.

there is a metadata.opf is in each books folder (and cover.jpg). Those are the backup for that book metadata as shown in Calibre

Anything that tampers with the Library folder can corrupt. Only Calibre should make changes. The DB is the link between the entry and the files. Delays can allow a cart before horse condition, thus the rule of NOT on a Network storage.

BTW your screenshot is NOT of Calibre Library (the typical folder where books are)

[BetterRed]

Originally Posted by Sys_eng

I looked there and I can see the the 4 custom columns that I created checked (with a check mark).

So where can't you see the columns - book list, book details, elsewhere?

BR

[Sys_eng]

Originally Posted by theducks

Restore expects everything else (other than the corrupted DB) to be in the normal place.

there is a metadata.opf is in each books folder (and cover.jpg). Those are the backup for that book metadata as shown in Calibre

Anything that tampers with the Library folder can corrupt. Only Calibre should make changes. The DB is the link between the entry and the files. Delays can allow a cart before horse condition, thus the rule of NOT on a Network storage.

BTW your screenshot is NOT of Calibre Library (the typical folder where books are)

Thank you, agin for your response and clarrfification.

You are correct, the screenshot I sent is not from Calibre, I accessed it through
Preferences > Miscellaneous > Open calibre cofiguration folder

Now, I have 2 questions:

1- My undestanding is that given that I have already performed the restore, the metadata.opf for each book has been overwritten and the custom columns settings have been lost. However, if I have a backup of the library which includes the metadata.opf files before restoration, I should be able to restore the custom columns through the metadata editor. The issue is that I could not find the option "Set Metadata from book files" . Question: I would appreciate that you point me to that option.

2- Does backuping up the library using Time machine considered tampering with the Library folder? If no, that is goog. If, yes, what is the best practice to have a disaster recovery plan?

[Sys_eng]

Originally Posted by BetterRed

So where can't you see the columns - book list, book details, elsewhere?

BR

In the book list, I can see all the books, all the columns (including teh custom columns), however, teh custom columns are empty, i.e. the data that I had (before restoration) is missing.

[theducks]

I don't know how it would behave doing piece meal.
Kovid would need to really say.

I suspect you would destroy the metadata.db, restore the json and all the metadata.opf's, then rebuild

WAIT for the GURU to bless this plan
That will leave those items added after the backup to be redone

[kovidgoyal]

If you have a backup use it to restore your library again. Restoring will restore custom columns and their data. The only way I knowof for that to fail is if you didnt actually do a restore but instead re-added the books to a library without the custom columns.

[Sys_eng]

Thank you so much, Kevin, for chiming in!
When you say "If you have a backup use it to restore your library again", doesn't that mean
doing that through Library > Library Maintenance > Restore Database on the main library folder? (which what I have already done)

or do you mean doing Library > Library Maintenance > Restore Database using a backup folder from x number of days before the library stopped loading normally?

[ownedbycats]

Not 'restore database'. Deleting the entire library and restoring it from a backup.