Requires CC V5.1.1 or later and calibre 2.54 or later
If CC and calibre are new enough then the CC can show custom "columns built from other column" (composite columns) in the top-level display of the Cloud Connection. CC requires that the values be stored in the calibre database by an optional calibre plugin. The plugin, a Library Closed plugin named Save Composite Custom Columns, is available in this MobileRead post, in calibre's Index of Plugins page and through calibre's Get Plugins feature (Preferences / Plugins / Get new plugins).
After you install the plugin in calibre, open your library in calibre's GUI. When you close the library (the GUI) the plugin will save the composite column information. You will see a notification while calibre is closing. Next do whatever you normally do to sync your library with the cloud provider. The next time CC opens that cloud library you will see the composite columns listed in the top-level display. The plugin will run every time you close your library so that the information in CC will be up-to-date.
If the plugin is not installed or has not run then you will not see the composite columns.
Download book performance: If your library has composite columns then the plugin also reduces the amount of time required to download books in the cloud connection. The performance increase can be as much as 3 to 5 seconds per book. See this FAQ answer for more information.
Hiding some composite columns: You may have composite columns that you don't want listed in the cloud connection top-level display. If so, while looking at that display tap the three dots to open CC's menu then choose "Choose items to display". Uncheck the columns you want to hide. Note: tap on the triangles to reorder the columns. A long-press on a triangle moves that column five rows.
The calibre command line: The plugin is not run when you use calibre's command line to modify metadata for books. You must run the calibre GUI to run the plugin and update the information.
Not running the plugin on some libraries: Once installed, the plugin will run on every library you open in the GUI. If you have libraries that you never use in CC's cloud connection and want to avoid the time the plugin takes to run, you can tell calibre not to run the plugin for those libraries. To do this, in calibre:
- Open the library you don't want to be processed.
- Click Preferences / Plugins
- Scroll to "Library Closed plugins". Click the triangle to show the "Save Composite Custom Columns" plugin.
- Click anywhere on the "Save Composite Custom Columns" text.
- Click on the "Customize plugin" button. Uncheck the "Run plugin on library ..." box.
You can later recheck the box if you change your mind.