This is a guide on how to allow people to connect to your DB using HeidiSQL. Before you look at this im using ArcEmu so it might be different for you.
1st step is to Connect to your HeidiSQL and click Characters DB not the Table!
2nd step click "Tools" at the top right
3rd step click User-Manager
4th step Type in User and Pass, The Host is your Hamachi IP/Domain Name
5th step pick the privileges you want the people to have
6th step click Add User and your done. Now people can connect if they know the information.