PostgreSQL

Update server for latest versions & install PostgreSQL

sudo apt update
sudo apt full-upgrade
sudo apt install postgresql

Add user for openhab

> sudo su postgres
> createuser openhab -P --interactive
Enter password for new role:
Enter it again:
Shall the new role be a superuser? (y/n) y

Create DB

> psql
psql (13.13 (Debian 13.13-0+deb11u1))
Type "help" for help.

postgres=# CREATE DATABASE openhab;
CREATE DATABASE
postgres=# exit