OK, that's a clear explanation.
I don't know if devs on this forum are server devs too. I would suggest that
irrespective of the presence of a server trusted cert (root.crt) that the
server be usable by the client, as his any time choice, for encryption only
and/or server/client authentication. Other RDBMS allow that : Oracle, Apache
Derby and MySQL. Although traffic encryption only raises security concerns, it
may be helpful in some limited cases.
Thank you for replying.