Thank you. Yes, I saw that bit of the documentation but I am not sure if i understand how this is supposed to work. My first attempt was to do something like this:
(defun org-roam-swap-databases ()
"Swap between work and personal org roam databases"
(if (equal org-roam-directory "/home/julian/Documents/Notes/")
(setq org-roam-directory "/home/julian/Documents/Personal/brain/")
(setq org-roam-directory "/home/julian/Documents/Notes/"))
Which works, but requires that the database is synchronized after swapping, and I am not sure if this is the best do do it.