I built a simple journal solution for myself two years ago. It sends an email every day and I can reply to it, and the response is stored in an SQLite database, in plain text. The db is on a remote server but copied to Dropbox every day (and in any case all the emails also exist in my sent folder). It is surprisingly effective at storing not just what I did with my day, but random thoughts and ideas, solutions to bug…
I tried using a database for personal notes many years ago and the problem I discovered was that I can't do a quick Ctrl+F to find previous scraps of knowledge.
Instead, I use plain "notes.txt" and use the editor's text search functions (including regex functionality) to locate things.
These 2 ways of finding text have very different ergonomics:
- SQL: select * from notes where description like '%ubuntu config%';
- text editor: Ctrl+F "ubuntu config"
Yes, one can write a program to "dump" the SQL database to a text file for subsequent search by a text editor. The problem is that it creates a read-only file that you can't edit-in-place. And one can also write a custom wrapper program in whatever language as a GUI for the database but now we're way past your simply "reply to email" paradigm and expending a lot of effort in "yak shaving" instead of just taking notes.
Not saying your system is bad for you but I'm guessing that most people would find the friction of a SQL database too high for freeform notes.