calibredb to get last_modified data

[meghane_e]

I'm picking back up a project from a few years ago:
https://www.mobileread.com/forums/sh...d.php?t=338741

I got most of my libraries merged but I never got around to cleaning up the extra backup libraries. I can Import the old backups with no problem. Calibre shows all of the timestamps I would expect to see for the dates of the imported library. But it turns out when I tried creating a custom column, Calibre immediately updates the last_modified column to today's date.

I want to keep a history of what the last_modified column contains prior to making any changes on a newly imported Library so that in the future I can figure out when a book was merged from another library and when.

Otw, I'm using calibredb to get the data and will create a small database to track changes there. Does anyone know if any of the plugins do something like this already? It seems unlikely, but figured I'd ask.

For each library directory (not the backup data directories)

calibredb list --with-library "C:\Calibre Library\Old Libraries\<library>" --f 
title,author,last_modified,timestamp > ".\<library>_premerge_dates.csv"

Notes: calibre.exe has to be shutdown. calibredb is finicky about the fields being grouped with no spaces.

[BetterRed]

Originally Posted by meghane_e

. . .
Does anyone know if any of the plugins do something like this already? It seems unlikely, but figured I'd ask.
. . .

Maybe the Audit Log plugin ==>> Index of plugins

BR

[Comfy.n]

Last Modified may be helpful

[meghane_e]

Originally Posted by Comfy.n

Last Modified may be helpful

This is awesome to know about going forward, but for the old libraries, especially pre-2020, this plugin requires "that you must add at least one custom date column to be able to use this plugin". So anything I do now will automatically change the default last_modified column, which would defeat the goal.

For the short term, I'm going to start by making a complete CSV file for each library that contains all the preexisting data, then add a #custom_last_modified column to each library. At that point, I'll have to probably write a script to to fill in the #custom_last_modified data using calibredb and the CSV file data. If I get really ambitious, I might add some other columns like #last_merged and #last_library that get filled in by a Template function. Considering the number of old libraries and backups, maybe a small database to track data changes would be more useful. Getting into the project-creep at this point.

Otherwise, thanks for the pointers!!

[DNSB]

You could use Job Spy to backup the last modified date and then restore it after you have made the changes such as adding a custom date column.

[meghane_e]

Originally Posted by DNSB

You could use Job Spy to backup the last modified date and then restore it after you have made the changes such as adding a custom date column.

Yes!! The JS+ Backup/Restore Last Modified dates does exactly what I want! JS+ does so many things, but it could really use some UI improvements. Anyway, it was much simpler than I previously thought once I had the right tools. Here are the steps (for future me, if no one else):

1. Order of steps matters.
2. Do NOT add a new column until after you've installed Job Spy and backed up the last_modified column.

3. Choose the target library. Verify the last_modified dates are correct.
4. Backup the Last-modified dates with the JS+ plugin:
Tools that are Metadata Related > Backup/Restore Last-Modified Dates > Backup Last-modified dates

5. Add a custom column through Preferences > Add a Column. Choose Type: Long Text. Restart Calibre.

6. Restore the Last-modified dates with the JS+ plugin:
Tools that are Metadata Related > Backup/Restore Last-Modified Dates > Restore Last-modified dates
7. Select all books (ie, Ctrl+A on Windows). Hit 'E' for a bulk edit.
8. On the Seach and Replace tab:

Search mode: Regular Expression
Search field: last_modified
Search for: ()
Replace with: \1
Destination field: #your_custom_column
Save the search, for instance: "Copy Last Modified
Click 'Apply' or 'Ok'