Question about accessing custom column information

wavioto · 03-13-2025, 09:16 AM

I've created a custom column in Calibre to store the contents of KOReader sidecar files (specifically, the notes generated while reading). I'd like to access the text from these notes and export them to Obsidian.

My initial attempt was to use Python and sqlite3 to directly access the Calibre .calnotes/notes.db file. However, I encountered errors, and after some research, I discovered that Calibre uses a custom tokenizer, which complicates direct SQL queries. I'm also not sure if notes.db is the correct database to be looking at for what I am attempting to do.

I'm a beginner in programming in general and Calibre internals, so I'm a bit lost.

Is .calnotes/notes.db the correct database?
If yes, what do I do for the custom tokenizer?

Is my approach valid or should I change it?

Any help and pointers would be greatly appreciated.

kovidgoyal · 03-13-2025, 09:18 AM

Use the database API
https://manual.calibre-ebook.com/db_api.html

In particular here you would use field_for()

wavioto · 03-13-2025, 09:39 AM

Thank you for the help.

Just curious, why was accessing the database file using sqilte directly not the correct approach?

kovidgoyal · 03-13-2025, 09:43 AM

Because its not a simple sqlite database. It uses lots of custom things such as triggers, custom auxiliary functions, views, etc etc etc.

wavioto · 03-13-2025, 09:45 AM

I see. Thanks again.

03-13-2025, 09:16 AM	#1
wavioto Junior Member Posts: 8 Karma: 10 Join Date: Mar 2025 Device: KT4 (kindle 10th generation)	Question about accessing custom column information I've created a custom column in Calibre to store the contents of KOReader sidecar files (specifically, the notes generated while reading). I'd like to access the text from these notes and export them to Obsidian. My initial attempt was to use Python and sqlite3 to directly access the Calibre .calnotes/notes.db file. However, I encountered errors, and after some research, I discovered that Calibre uses a custom tokenizer, which complicates direct SQL queries. I'm also not sure if notes.db is the correct database to be looking at for what I am attempting to do. I'm a beginner in programming in general and Calibre internals, so I'm a bit lost. Is .calnotes/notes.db the correct database? If yes, what do I do for the custom tokenizer? Is my approach valid or should I change it? Any help and pointers would be greatly appreciated.

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03-13-2025, 09:18 AM	#2
kovidgoyal creator of calibre Posts: 45,171 Karma: 27110894 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Use the database API https://manual.calibre-ebook.com/db_api.html In particular here you would use field_for()

03-13-2025, 09:39 AM	#3
wavioto Junior Member Posts: 8 Karma: 10 Join Date: Mar 2025 Device: KT4 (kindle 10th generation)	Thank you for the help. Just curious, why was accessing the database file using sqilte directly not the correct approach?

03-13-2025, 09:43 AM	#4
kovidgoyal creator of calibre Posts: 45,171 Karma: 27110894 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Because its not a simple sqlite database. It uses lots of custom things such as triggers, custom auxiliary functions, views, etc etc etc.

03-13-2025, 09:45 AM	#5
wavioto Junior Member Posts: 8 Karma: 10 Join Date: Mar 2025 Device: KT4 (kindle 10th generation)	I see. Thanks again.