Restore custom columns

[Sys_eng]

Originally Posted by ownedbycats

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

Thank you, for the clarification.

[ownedbycats]

Also, if there's new books added since your last backup, use 'add from folders and sub-folders,' it should import the OPF information.

[Sys_eng]

Thank you so much, guys for your help! (ownedbycats, Kovid, theducks and BetterRed).

Using Apple Time Machine, I found a backup from a couple of days before the database got corrupted. I successfully restored the database from that backup; and I got the custom columns back (only one book was added to the library since the corruption).
As a new user to Calibre, I learned the following:
(1) I shouldn't put Calibre library on a Cloud service. I got into this situation because of putting the library on iDrive and trying to move it from iDrive to Mac (after reading about the issues associated with Cloud hosting)
(2) I should and will keep the Calibre library on Mac to take advantage of the TimeMachine backup.
(3) The safest way to access the library remotely is through COntent Server.

[kovidgoyal]

yes I mean revert your library to your latest backup. If the columns are already there you are done. If not try running the restore database function with the reverted folder as your library.

[Sys_eng]

Thank you again, Kovid! It worked as I shared in my previous post

[DNSB]

Originally Posted by 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?

No, the backup being referred to is when you right-click on the Library icon and see Export/import all calibre data. If you haven't done that previously, it's too late to do so now. I use that functionality for creating a backup that can be easily moved between Linux, MacOS and Windows and allows restoring your entire library after a disaster. I also back up my settings directory and libraries using file backup (easier to restore a single file from).

I spent too many years in IT where the motto of many is "I know I'm paranoid. I just don't know if I'm paranoid enough" to be happy without multiple tested backups.