Project moved. https://github.com/textbrowser/biblioteq
"Please download from https://github.com/textbrowser/dooble/releases."
This project is not monitored. SF is abandoned.
BQ is extensible, however, it's not automatically extensible. Such a function is beyond the current scope of the program because it requires a significant effort.
SQLite is offered for people who are uncomfortable with PostgreSQL. I prefer PQ, however, it requires learning and may not be suitable for everyone. It does offer networking and redundancy. Well, it offers many more things which SQLite cannot. On Windows, I use it as a client and it works well. As an alternative, if you have another machine, you could install Linux on it and PostgreSQL. Anyway, many possibilities. https://www.pgadmin.org/videos/ Good luck.
The included PQ SQL script is for PQ and not for SQLite, hence the assigned file name. In BQ, see the File menu. There, you'll be able to select an SQLite file name and BQ will prepare the SQLite database for you. PostgreSQL and SQLite are not symmetric database engines. They offer different and similar syntax. OK, done for today. Please read the documentation and use common sense. :)
If you cannot configure PQ, BQ also supports SQLite.
PostgreSQL assumes a level of understanding by the user. I suggest learning to administer and prepare it outside of any application. I know that it works with BQ but I don't have the time to document its preparation on Windows. The user is expected to understand PQ. https://www.postgresqltutorial.com/install-postgresql/ https://www.postgresqltutorial.com/connect-to-postgresql-database/