mySQL public access from dynamic ip address

I've read a few forum discussions like this one that suggest using an SSH tunnel and only allowing access to MySQL from Local Host.

This guide should explain how to set that up:

Create an SSH Tunnel for MySQL Remote Access

I'm sure there are other ways to do this, but what I've read suggests that's the best method if you're looking for something that's secure and fairly straightforward. That said, I haven't done this myself, so you should investigate to see if it sounds right for you.

Hi CassandraD, thank you. that is good. what I want to do is that i want to store a machine's parameters like input/output status (analog value, On or off, etc) on your linode database_mySQL from raspberry pi which have dynamic ip address. then the mySQL's data should be accessible/public from any computer which have dynamic ip address too to retrieve data or create report/summary. does your linode's database work in that way? sorry i'm new to this networking. thanks for advice.
Best Regards,
Wathan